Construction is under way in the United States of a $100 million, seven-storey exhibit featuring the replica of a Northern Territory gorge.

The Umbrawarra Gorge near Pine Creek, 200 kilometres south of Darwin, will be the centrepiece of the exhibit at the National Aquarium at Baltimore, outside Washington.

Eight freshwater crocodiles have already been flown to the US to be part of the exhibit.

Federal Member for Lingiari Warren Snowdon visited the site and says one-point-seven million people visit the aquarium each year.

"They propose to run a series of events over a period of 12 months around the development and the opening of this major attraction," he said.

"The potential of what that might be in terms of tourist visitation, because if we're prepared to think along those terms for the investment of not a significant amount of money, I think we would get an enormous spin off."

Mr Snowdon says the US will import as much flora and fauna as possible.

"Not only are they getting it from Australia but there are a range of sources on the open market already and I'm not sure exactly to what extent they'll do an exact reproduction of the habitat," he said.

"There's no question about what their desire is, even to the extent of trying to introduce a component of Indigenous art."

The replica will open in April 2005.