Up to 60,000 operations are at risk of cancellation or delay every day that junior doctors go on strike in planned industrial action next month, Health Minister Alistair Burt has said.
Mr Burt described the strikes as "entirely avoidable" and urged the British Medical Association (BMA) to avert anything that risks harm to patients during three days of action by junior doctors in England.
He insisted Health Secretary Jeremy Hunt has not ruled out mediation through the Advisory, Conciliation and Arbitration Service (Acas), as requested by the BMA.
Shadow health secretary Heidi Alexander said the situation made her "angry and sad" adding: "It didn't have to be this way."
Answering Ms Alexander's urgent question in the Commons, Mr Burt said: "It is regrettable that junior doctors have voted for industrial action which will put patients at risk and see between 50,000 and 60,000 operations cancelled or delayed each day.
"I would therefore call upon you to join the Government in calling on the BMA, as it prepares for unprecedented strike action, to come back to the table.
"Come back to the table for talks about the new contract for junior doctors.
"The Government remains firmly of the view that the strike by junior doctors is entirely avoidable and calls upon the BMA to also do all it can to avert any action that risks harm to the patients we all serve."
Mr Burt said the Government would reserve the right to change doctors' contracts if an agreement cannot be reached to facilitate the "truly" seven day NHS promised by the Tories during the general election.
He said: "You have called for the parties to go to Acas.
"The Secretary of State is not ruling out conciliation, we have always been willing to talk.
"The Government has repeatedly appealed to the BMA to return to the negotiating table and that offer is still open.
"We believe that talks, not strikes, are best for patients and for junior doctors.
"The Secretary of State has said that talks can take place without preconditions other than that an agreement should be within the pay envelope, but the Government reserves the right to make changes to contracts if no progress is made on the issues preventing a truly seven day NHS, as promised in the manifesto and endorsed by the British people at the last election."
Ms Alexander said: "The truth is if we'd had a little less posturing and a little more conversation from the Health Secretary, this whole sorry episode could have been avoided
"Do you agree with me that over the course of the next week, everything that can be done, should be done to stop the three days of planned industrial action?
"You said the Health Secretary is not ruling out going to Acas, so why then did he yesterday appear to dismiss this idea of independent mediation? Does this seeming flippant rejection of the need for independent mediators to prevent industrial action not show a casual disregard for patient safety?"
The shadow secretary of state added: "The way the Health Secretary has handled these negotiations has been appalling."
Ms Alexander said "negotiation by press release" was the wrong way to go about the dispute.
She said: "Do you understand junior doctors are particularly angry about the way in which the Health Secretary has repeatedly conflated the reform of the junior doctor contract with seven-day services?
"Junior doctors already work weekends. They already work nights. And for the record, there isn't a single junior doctor I have met over the last few months who wouldn't drop everything to respond to a major terrorist incident."
Ms Alexander said: "To suggest otherwise is an insult to their professionalism."
She said the "fundamental question" was why ministers appeared determined to "continue this fight" in the context of growing deficits, a mental health crisis and a bleak winter.
In response, Mr Burt said: "I agree we don't need to be here - that's why the Secretary of State has kept his door open all the time.
"After starting negotiations three and a half years ago in order to seek to conclude this, that door remains open. It is for the BMA to come through and say they want to continue negotiations which they abruptly left over a year ago.
"Everything can and should be done to avert the strikes ... it would help with an unequivocal statement by the Labour Party front bench that it does not support strike action by doctors. I wait to see if that is forthcoming."
Mr Burt said talks had to be under way in order for the Acas conciliation service to be brought in.
He added: "For you to talk about a challenge to safety comes ill from a party that presided over Mid Staffs.
"The point of this is to say that since he took office, the Secretary of State has quite plainly and to everyone's knowledge made safety in the NHS his prime consideration.
"That is why he wants to see a seven day NHS to recognise the issues that have arisen at weekends."
On the threats of a terror attack, Mr Burt added: "(Sir Bruce Keogh's) point in relation to an emergency situation is this: no one doubts for a second should there be an emergency in this capital as there were in Paris, every available doctor would report for work, every person involved in the medical staff would do so.
"If it took place on a day of a strike when they weren't already in the hospitals in the numbers they would need to be, it takes time to get in. That was his concern for patient safety and I think that is a reasonable one."
Mr Burt added: "The Secretary of State has been patient, he's been fair, he's been clear it's about safety. Negotiations should be returned to as soon as possible and it would help if everyone said so."
Conservative Tania Mathias (Twickenham), an NHS doctor, said she had chosen not to take part in the ballot which revealed overwhelming support for industrial action.
She added: "I would urge the minister and the BMA, I would urge them all to return to the negotiating table, but without any preconditions.
"I am surprised if my colleagues and the people I know will go on strike. I would be very surprised.
"I can't myself imagine that, therefore I think there is an opportunity to go negotiate and if that does not succeed, then to have Acas."
Mr Burt said: "You are absolutely right. You believe quite rightly there should be negotiations and the Secretary of State has said that.
"There are no preconditions beyond what the secretary has said about his right to ensure a manifesto commitment is delivered."
Labour's Nic Dakin (Scunthorpe) said: "Why not just go straight to Acas? From my constituents' point of view, something has broken down here and it needs fixing. Why not just get on with it?"
Mr Burt said: "Because the last time an independent body looked at this matter, which is what the Secretary of State did after negotiations broke down before it went to an independent body, the Doctors and Dentists Review Board, the BMA took part in that, they made representations to it.
"That independent body reported and the BMA still did not do anything. Those recommendations form the basis on which negotiations can take place. If those negotiations are not successful, that is when you have conciliation."
Tory Christopher Chope (Christchurch) said: "Isn't the root problem here the NHS is a monopoly employer of junior doctors?
"If the veterinary profession can provide 24/7 care for sick animals, why can't junior doctors provide the same for sick people?"
Mr Burt replied: "The Commonwealth Fund said recently the NHS was the best in the world. The NHS staff, therefore, by implication are the best in the world.
"They do an extraordinary job and junior hospital doctors do a fantastic job. Patient satisfaction is at an extremely high level, we want to see that continue.
"I don't think there is any particular reason why the NHS employers - who are also calling for negotiations to continue and for strike action not to take place - aren't in full view of what they need in terms of staffing to create an even safer health service."