Jeremy Corbyn says the Government has been "running down the clock" and "bullying and threatening" MPs in order to force through Theresa May's Brexit deal.
The Labour leader also refused to say whether his party would offer an option to remain in the European Union during a second round of indicative votes in the House of Commons on Monday.
Mr Corbyn was speaking from Newport in South Wales on Saturday as he joined Labour candidate Ruth Jones ahead of the Newport West by-election next week.
Reporters were earlier barred from attending a speech the Labour leader gave to party members at the Newport Centre leisure complex.
But speaking from the suburb of Pillgwenlly, Mr Corbyn said his priority was to end the "chaos" in Westminster by reaching out across the House of Commons and getting support for Labour's alternative plans for a Brexit deal.
Asked if Labour's indicative vote would include an option of giving the public a confirmatory referendum on any Brexit deal, Mr Corbyn said: "That is the Labour position so far but there hasn't been enough support for that across the floor in the House of Commons.
"But the absolute priority at the moment is to end this chaos the Government has brought us to by their endlessly running down the clock and basically bullying and threatening people. The bullying hasn't worked the threats hasn't worked. It's time now for the sensible people to take over.
"This is a very dangerous period because if we crash out without a deal then the supply chains get interrupted, jobs are at stake, and also the sense of security of many EU nationals living in Britain, and of course British people living across Europe."
Mr Corbyn refused to say whether the option to remain would be on a Labour ballot paper, saying: "The question on the referendum was a choice of all options."
Mr Corbyn said Labour would propose a deal involving a customs union with the EU to protect the issue of a hard border in Northern Ireland.
He said: "We are working very hard on that and reaching out to people all across the Commons, and I have been doing that all this week and obviously I'll be doing that all this weekend."
Mr Corbyn added: "However people voted in the referendum, no-one voted to lose their jobs, no-one voted to be worse off, and no-one voted to deregulate our society.
"I think the obvious choice is the one I suggested which would be a good economic relationship with Europe that could be negotiated. I'm convinced at that after spending a lot of time meeting with and talking to officials in Europe."
The Newport West by-election, triggered by the death of Labour MP Paul Flynn, will take place on April 4.