Banks in Greece and the country’s stock exchange will be shut all week in a sign of the deepening financial crisis.
The drastic move comes after people rushed to withdraw their cash amid panic ahead of the referendum on bailout terms.
Under the controls, there will be a daily €60 limit on withdrawals from cash machines, which will reopen on Tuesday.
The Foreign Office has warned British tourists to take enough cash to cover emergencies in case cash machines are emptied.
It said: “Visitors to Greece should be aware of the possibility that banking services – including credit card processing and servicing of ATMs – throughout Greece could potentially become limited at short notice.”
The euro fell sharply against the dollar amid investor jitters of a Greek debt default and exit from the eurozone.
Speaking in a televised address, Prime Minister Alexis Tsipras urged calm and insisted bank deposits were safe.
He blamed European partners and the European Central Bank for forcing Greece’s hand.
And he said the latest developments would not halt the planned referendum next Sunday.
But queues at petrol stations and the declining number of bank machines still dispensing cash underlined the scale of the country’s economic plight.
European creditors have refused a request to extend Greece’s international bailout beyond Tuesday, until after the referendum.