The sums raised from the $500-a-head dinner, held 10 days ago in the plush New York Sheraton Hotel and attended by Sinn Fein leader Gerry Adams, dwarf the amount of money Fianna Fail raises from its heavily-criticised tent at the Galway races.

Organised by Friends of Sinn Fein and attended by 800 guests, the Manhattan dinner would have grossed in the region of $400,000.

But, allowing for expenses of $125 a head, the net take is likely to have been around $300,000.

Tyrone-born multi-millionaire Pat Donaghy, who runs a hugely successful construction business with sales of over $2bn based in New York, is understood to have been one of the main organisers of the event, which was attended by a number of wealthy businesspeople.

The 65-year old Donaghy, who has been central to the party's fundraising efforts in the US, is said to be close to senior members of Sinn Fein, including Adams and Martin McGuinness.

Adams was given permission by the US government to attend the fundraiser at the Sheraton.

Last year, he was forced to address the audience by a live satellite link from Dublin because of the US administration's annoyance at Sinn Fein's position on the PSNI.

Commenting on the Manhattan fundraiser, Labour party leader Pat Rabbitte said yesterday that when a small party, such as Sinn Fein, commands such resources, "it seriously skews the pitch". He added that for a party that "spends so much time railing against big business in Ireland", Sinn Fein didn't seem to "have any scruples coming back with buckets full of money from big business in the US".

The level of Sinn Fein's resources has long been a source of contention with the other political parties. The party has a network of more than 40 offices in the 32 counties, something none of the other parties have been in a position to match. Last year, accounts published by Sinn Fein showed the party spent just under 2m running its operations north and south in 2003.

Sinn Fein has raised over $7m in the US since 1995 when Bill Clinton lifted a ban on its fundraising. In the 12 months to April last, the most recent figures lodged with the US Department of Justice, the party raised $564,000 there.