The Government has a grip on the migrant crisis at Calais, Philip Hammond has insisted as David Cameron faces calls to break his holiday and witness its impact "first hand".
The Road Haulage Association (RHA) has urged Mr Cameron to visit Calais and see what lorry drivers are experiencing for himself.
But emerging from a long meeting of the Government's emergency Cobra committee, the Foreign Secretary said the Government had the crisis in hand.
Mr Hammond said 100 additional guards would be on duty at the terminal in Calais, while UK Border Force officials would start working inside the Eurotunnel control room tonight.
He said: "I think we have got a grip on the crisis. We saw a peak last week, since when the number of illegal migrants has tailed off.
"We have taken a number of measures in collaboration with the French authorities and Eurotunnel which are already having an effect and over the next day or two I would expect to have an even greater effect."
Mr Hammond did not directly address Mr Cameron's absence, due to end on Thursday before he takes further time away from the office.
The RHA's call comes as pressure on the Government to secure a long-term solution to the emergency continues.
RHA chief executive Richard Burnett said: "Without witnessing the mayhem at Calais first hand, neither the Prime Minister nor his advisers can fully grasp the severity of the situation.
"I have therefore issued an invitation to David Cameron to travel with him across the Channel to see for himself the appalling conditions that drivers are facing.
"I made the journey five weeks ago and I have been back to Calais today to assess the current situation and to establish for myself the problems facing our drivers."
Lorries have repeatedly been targeted by migrants desperately trying to reach Britain.
The crisis is said to have cost the economy millions of pounds as hauliers are forced to dispose of contaminated goods and wait in lengthy queues on the M20 in Kent.
Mr Burnett has written to the Prime Minister requesting an urgent meeting.
Following the Cobra meeting, Mr Hammond said co-operation with the French authorities and Eurotunnel had improved.
He said: "I'm pleased to say we have seen a much improved level of co-operation and collaboration with Eurotunnel over the past 48 hours, with trains being cancelled where appropriate and in some cases trains being reversed back into Coquelles where there is a danger of illegal migrants being on board.
"From this evening, UK Border Force and French police will have a presence in the Eurotunnel control room at Coquelles and that will greatly enhance the practical collaborative working at the site.
"I also understand this evening the company has accepted our offer of additional guards and we expect up to 100 additional guards to be deployed into the terminal area
"The fencing work is proceeding on schedule, we expect that to further enhance security.
"Meanwhile on this side of the Channel we are in the final stages of procuring some additional facilities to support the (Operation) Stack lorry-holding operations so that when it is switched on again later this week the disruption on the motorways will be less."
Mr Hammond added: "Finally, we are working very closely with the French authorities on putting together a joint plan to support returns to country of origin by illegal migrants seeking to enter the UK and those who are in the Calais area.
"France and Britain are determined to work together to lead the campaign in Europe for a more robust approach by the European Union to ensuring we get the returns of migrants to their countries of origin."