The inquiry was ordered by Congressman Lee Hamilton, chairman of the influential European and Middle East sub-committee of the Foreign Affairs committee, after he read an article in Saturday's Independent.
It disclosed that the Ministry of Defence and Westland Helicopters invited British defence companies to tender for a dollars 5bn ( pounds 2.7bn) contract, knowing certain weapons in the package would be banned by Congress.
The proposed contract was to arm a consignment of 88 battlefield attack helicopters destined for the Middle East with an integrated weapons system which included anti-tank missiles and rockets.
The helicopter to be armed was the Black Hawk, which Westland makes under licence from Sikorsky, an American company.
Mr Hamilton has now instructed staff who run his committee to investigate the allegations. His assistant, Chris Mehl, said: 'Mr Hamilton sent your report to them and told them to look into it. I do not yet know if this will lead to formal hearings by the committee or just an officer inquiry. The staff will make preliminary inquiries and report back.'
A Sikorsky employee has claimed in a Washington court that Westland was to be used to supply armed Black Hawks to Saudi Arabia because Congress would have blocked such an export by Sikorsky.
The employee, former Lieutenant Colonel Thomas Dooley, claims Westland and Sikorsky were also part of a conspiracy in which two Saudi Arabian princes were to be bribed with 'commissions' to award them the Black Hawk contract.
Mr Dooley claims another reason that Westland was used was because US companies are banned by the Corrupt Practices Act from paying 'commissions' to agents or customers. British companies are not.
There is no suggestion that what Westland and the MoD proposed was illegal under United Kingdom law. But if American companies conspired to avoid US law that could be in breach of the US Arms Export Control Act or the Corrupt Practices Act.
Westland denies the Black Hawk contract, which is still being negotiated with Saudi Arabia, was part of a conspiracy. The company says the contract was part of a British Government-negotiated order to sell defence equipment worth dollars 42bn (pounds 22.5bn) to Saudi Arabia over 20 years.