The proposal for "floating hotels" is a revival of an idea which was initially rejected two years ago.
However, Qatar is now seeking to strengthen its presence in the cruise ship market and the idea to house fans during the tournament has been re-floated.
The QTA announced the proposals at a trade conference in the US over the weekend.
In a statement on the official Qatar News Agency, the QTA said: "Over the past few years, QTA established a number of strong relationships with international cruise operators as well as with other specialists involved in the industry.
"This has proved to be of great importance especially that Qatar will be extensively benefiting from cruise ships over the 2022 World Cup, as a means of providing additional accommodation supply for fans and visitors over the period.
"QTA will be contracting a minimum of 6,000 rooms on cruise ships for 2022 tournament."
A spokesman for the authority confirmed on Monday that this equated to space for 12,000 fans.
It is not yet clear where the cruise ships will be docked but as part of Qatar's huge $200-billion (190-billion euros) capital spending project, ahead of football's most prestigious tournament, the country is building a new port south of the capital, Doha.
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FIFA guidelines say Qatar must have 60,000 rooms available for fans by 2022.
Ambitious Qatar though has pledged to make 100,000 rooms available.
This however may lead to thousands of hotel rooms going empty once the tournament, being played in November and December 2022, finishes.
Housing football fans offshore may ease any problems of hotel room over-capacity and it could also help with the thorny issue of alcohol.
Qatar is a dry country where local Qataris cannot drink alcohol, but expatriates are allowed to but only if they have the correct permit.
The authorities in Doha have previously said that alcohol will be made available for fans in certain areas in seven years' time.
One of the 2022 tournament's official sponsors will be the giant American brewer Anheuser-Busch, maker of Budweiser lager, the "official beer" of the World Cup.
The cruise ship proposal was first proposed in 2013 but then quietly dropped by the authorities.
Some one million people visited Brazil for the last football World Cup in 2014.