The Schengen agreement is under threat as the migrant crisis continues Dimitar Dilkoff/AFP

Labour have called on EU leaders to examine the Schengen agreement after German Chancellor Angela Merkel warned that the passport-free treaty could be under threat because of the ongoing migrant crisis. The UK remains outside of the agreement, but Labour's immigration spokesman told IBTimes UK that there has to be an examination of Schengen.

"In the conference that is coming up with ministers on 14 September, we will be arguing that they should at least review [Schengen] and how it is operates because of the fact that people can enter Greece and travel unended through the whole of Europe to as far as Calais," David Hanson MP said.

The immigration spokesman talked ahead of Yvette Cooper's speech on the issue this morning (1 September), where the Labour shadow home secretary said the UK could take on 10,000 refugees and claimed there were "serious questions" to be answered on Schengen. Hanson also said Labour have "consistently" called on the government to take more people particularly from Syria.

"They've got to urgently establish assessment centres at the main points of hot spots, which are in Greece and some parts of Southern Italy. At the moment, you have people coming across who are claiming asylum and migrant status, some of whom are going to be economic migrants. The first thing we need to do is assess to identify and look at what is needed," Hanson added.

The comments come after Merkel warned Europe could bring back border controls unless countries across the continent take on more asylum seekers. "If we don't succeed in fairly distributing refugees then of course the Schengen question will be on the agenda for many," Reuters reported Merkel saying. Germany is expected to open its doors to 800,000 asylum seekers this year, according to official figures.

A day in the life of migrants in the 'Jungle' preparing to cross into BritainIBTimes UK

The Schengen agreement covers 26 countries across the EU but Ireland and the UK have negotiated opt-outs. Top EU ministers are expected to meet on 14 September in Brussels to discuss the migration crisis. Since the start of the year 340,000 migrants have reached the EU and between 3,000 and 5,000 are estimated to be in the French port of Calais.

Their attempts to get into the UK have disrupted Eurotunnel service and haulage drivers travelling to and from the continent. The French government has stepped up security around the port and David Cameron has promised more sniffer dogs and fences to stop the migrants. The prime minister made the move after promising to provide £7m ($10.7m) of funding to help the French authorities.

"We have got people trying to illegally enter our country and here in Britain we have got lorry drivers and holidaymakers facing potential delays. We are going to take action right across the board starting with helping the French on their side of the border. We are going to put in more fencing," Cameron said on 31 July.