David Cameron has said he is prepared to close Britain's borders to Greek immigrants in the event that Greece was forced to leave the eurozone.
Giving evidence to the House of Commons Liaison committee on Tuesday afternoon, the prime minister said he was "prepared to do what it takes" to prevent a large influx of Greeks fleeing a deep recession.
“We obviously have contingency plans for all sorts of eventualities," he said.
"The legal position is that if there are extraordinary stresses and strains, it is possible to take action to restrict migratory flows but obviously we hope that doesn’t happen."
In May the Home Office revealed it was planning for a possible large increase in immigration from Greece and other European Union nations in response to the crisis in the euro.
Home secretary Theresa May said that "work is ongoing" to deal with large movements of people in the event of the break-up of the single currency.
Should Greece leave the euro, a 'Grexit', and go bankrupt, millions of people could lose their jobs and may look for work abroad.
There are fears too of the contagion spreading to other weak eurozone countries.
Britain, as a non-eurozone country, may be seen as an attractive alternative.
However, May did not indicate the sort of response that was under consideration.
In normal circumstances the government's hands are tied because EU nationals are largely entitled to live and work anywhere in the single market.