There's a chance an Auckland-based America's Cup could drive some tourists away.

A government report has found that hosting the regatta would be worth between $600 million and $1 billion to the economy.

However, the Property Institute is casting doubt over those figures and claim those numbers are too ambitious.

CEO Ashley Church says if the Rugby World Cup's anything to go by these kind of reports tend to set ambitiously high targets.

Church wants to see the event go ahead but says it's likely the study didn't take all of the relevant factors into account - especially the 'displacement effect'.

He explained, "It basically means that people who would have otherwise have come during the period choose not do so because the Cup is on and they avoid their travel plans.

"[I'm] very, very keen to see it happen [but I'm] concerned that the expectation that's been created is going to put us into an impossible position, where we'll almost inevitably fail to meet that benchmark."