Thousands of Australians who have already booked and paid to attend the Anzac Day centenary dawn service in Gallipoli stand to miss out because only a restricted number of tickets will be issued via a ballot.
The federal government has warned Australians to not hand over money to tour operators promising a place at the service before the national ballot.
The ballot, to be held between November and January, will allow 8000 Australians, 2000 New Zealanders and 500 ''official representatives'' tickets to the 2015 dawn service and the Lone Pine service.
Of the 8000 tickets allocated to Australia, only 3000 double passes will be available to the general public.
But travel companies in Australia and Europe have been taking bookings for tours worth thousands of dollars, guaranteeing attendance to the official services in their itineraries.
Tour operator Paul Murphy says he has more than 1800 people booked on his Military History Tours. On his website the itinerary states that the tour will include ''attendance at major services on ANZAC Day''.
But Mr Murphy said once people booked they were informed about the ''ballot situation'' by the company's newsletters.
''People don't buy it off our itinerary, they buy it off the information they get when they book,'' he said. ''We started marketing our tour program in 2009.''
Veterans Affairs Minister Warren Snowden warned Australians against buying tickets for the dawn service, before the national ballot opens.
''Frankly if people have been selling tickets to an event they don't own, they are acting irresponsibly,'' he said.
''It's misleading, it's wrong, they should cease it and if they've taken money from people, they should give it back.''
More tourists are likely to participate in private ceremonies on ships anchored in Anzac Cove than be at the official ceremony on land, the founder of Captain's Choice cruises, Phil Asker, said.
''There will be between 10,000 and 12,000 people docked on ships,'' he said. ''A lot of people will miss out on Anzac Cove or North Beach for the actual dawn service because that is obviously going to be well and truly limited, and probably correctly so. It's got so overcrowded in recent times, that if everyone showed up … it just would not work.''
Mr Asker said guests who did secure a ticket in the ballot for the official service would have to make their own arrangements on the day.
''We'll provide a bus down to the site, then they'll have to do their own thing until we pick them up later in the day,'' he said.
On board his chartered ships that will be anchored off Anzac Cove, Mr Asker will host private dawn services for his 500 guests.
The Department of Veterans' Affairs will conduct a public information campaign before the event to discourage people from ''showing up'' without a ticket, a spokeswoman said. The number of cruise ships allowed to enter Turkish waters is yet to be arranged, she said.