Holidaymakers heading to Greece this summer are being warned to take euros with them as cash reserves in the country reach a critical level.

Withdrawals have been limited to 60 euro a day for locals amid fears the country is heading towards a financial collapse.

Banks closed on June 28 and will stay shut until at least July 6, according to the British Foreign Office.

The latest advice from the Foreign Office says: "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.

"At this time, you can continue to withdraw cash using your card as normal, up to the daily limit imposed by the Greek banking system, usually 600 euro, or the daily limit imposed by your card issuer, as long as the ATM has been replenished.

"While banks are closed in Greece and some withdrawals are limited, make sure you take sufficient euros in cash to cover the duration of your stay, emergencies, unforeseen circumstances and any unexpected delays."

Tourists are also being warned about potential dangers to their personal safety with regular demonstrations and strikes taking place.

"You should take appropriate security precautions against theft," the Foreign Office said.

"There are regular strikes. These are sometimes called at short notice and can cause disruption to public transport in and out of Greece, including air travel and ports.

"Demonstrations take place regularly in central Athens, and have also taken place in other towns and cities."

Abta (Association of British Travel Agents) said there are "mixed reports" about the availability of cash from ATMs.

"We advise holidaymakers and travellers heading out to Greece this summer to take enough euros in cash to cover all of their needs," a spokesman said.

"Holidaymakers should check how much cash their travel insurance policy covers them for and should take appropriate security precautions against theft such as using their hotel safe or splitting cash up between their party.

"Reports from our members and holidaymakers on the ground suggest that it is very much business as usual in Greece and we have no indication that holidaymakers will be disrupted."

A referendum will be held in Greece tomorrow on an international bailout.