The Greek Tourism Confederation said it has seen a 30 percent drop in last-minute bookings, which typically account for one-fifth of bookings to the country.

"We believe that a swift conclusion to the Greek government's negotiations with the country's creditors would still give us sufficient time to make up for the loss - as far as possible - in last-minute bookings," Andreas Andreadis, chairman of the confederation, said.

Travel website Opodo.de (>> eDreams Odigeo SA) said Greece flight bookings from Germany, which had been tracking the levels of the previous year, suddenly dropped off after June 26, when talks broke down between Greece and its euro zone creditors.

Between June 27 and July 6, daily flight bookings have been down most days by around 30-35 percent from the previous year, with one day showing a decrease of 68 percent, it said in data made available to Reuters.

Other German travel sites Kayak.de and Swoodoo.de, part of the Priceline Group (>> Priceline Group Inc), said in the week before Sunday's referendum on whether to accept the terms of a bailout searches for flights to Greece were down 8 percent compared with the previous year.

Skyscanner.de said searches for flights were down 10 percent and flight prices had dropped around 7 percent.

The reduction in bookings seems particularly to affect Germans. Skyscanner said earlier this week that interest from Britain and Spain had actually increased. Some European tourists were switching holiday plans to Greece from Tunisia following an attack on tourists there.

Many Greeks blame Germany for their country's debt woes, and in past years some Germans have cancelled trips to Greece because of fear of hostility from the locals. In 2012, anti-German sentiment at protests in Athens led to bookings from Germans falling around 30 percent.

This time, the crunch has come later in the year, and with 70 percent of the 2.5 million Germans holidaying in Greece travelling on package holidays, many trips are long since booked. With no refunds being offered, cancellations are not being reported and tour operators have said overall demand this year was strong.

CAPITAL CONTROLS

Capital controls imposed since June 29, which limit withdrawals from cash machines and payments abroad, mean governments have advised tourists visiting Greece to bring euros in cash for spending money.

Several airlines, including Emirates [EMIRA.UL], Qatar Airways and Turkish Airlines (>> Turk Hava Yollari AO), have stopped allowing Greek travel agents to sell their tickets, said Lysandros Tsilidis, president of the Hellenic Association of Travel and Tourist Agencies (HATTA).

"We consider this inexcusably tough," he said. "Even though they have been our partners for years and even though we have already paid 82 percent of what we owe to them during this season."

Airlines association IATA has set up emergency procedures for its clearing house system which serves 400 airlines. Travel agents in Greece will be required to send funds to a Greek bank account on a weekly rather than fortnightly basis from July 15. Under the capital controls, the money still cannot leave the country.

"While we understand and sympathise with the difficulties facing agents on the ground in Greece, this action is being taken in response to the extraordinary circumstances facing the country," an IATA spokesman said.

Turkish Airlines and Emirates confirmed they had stopped issuing tickets through Greek tour operators and travel agents. Emirates said its customers could still book tickets for its flights via its sales office in Athens, on the phone or online.

"These measures will be reviewed again in due course and we apologise for any inconvenience caused to both our customers and valued travel partners in the interim," the Dubai-based airline said in an emailed statement to Reuters. Qatar Airways did not respond to requests for comment.

Other major European carriers are continuing to sell tickets, although customers with Greek bank cards may have difficulty paying airlines that process payments elsewhere.

Low-cost carrier Ryanair (>> Ryanair Holdings plc), which usually sells its tickets online, said last week it would allow Greek customers to pay with cash.

Lufthansa (>> Deutsche Lufthansa AG) said it and group airlines Austrian, Swiss and Brussels were continuing to sell tickets paid for by credit cards with no restrictions.

AerCap (>> AerCap Holdings N.V.), the world's largest independent aircraft leasing company, which counts Aegean Airlines (>> Aegean Airlines S.A.) as a customer, said it was seeing no problems with payments yet but there may be a temporary decline in revenue from Greece.

"Maybe we'll take a couple of airplanes back and move them somewhere else," CEO Aengus Kelly said in Dublin on Wednesday. "But we would certainly be of the opinion that in the long run, the tourism demand will still be there in the Greek market."

(Reporting by Victoria Bryan and Lefteris Karagiannopoulos; Additional reporting by Peter Maushagen Lefteris Karagiannopoulos, Nadia Saleem, Ceyda Caglayan and Conor Humbphries; Editing by Peter Graff)

By Victoria Bryan and Lefteris Karagiannopoulos