A Liberal fundraising arm attached to Federal Treasurer Joe Hockey’s electorate has been forced to repay another $22,000 in political donations made by a company at the centre of a corruption inquiry.

The North Sydney Forum, which raises political donations for the NSW Liberal Party, repaid $11,000 in February last year when concerns about Australian Water Holdings (AWH), a company connected to disgraced Labor figure Eddie Obeid, first emerged.

Following an inquiry from the ABC about a further donation made by AWH in 2009, Mr Hockey’s office has confirmed another $22,000 in political donations has been refunded.

The Government confirmed earlier in the week that it had already refunded $11,000 but at the time made no mention of the further $22,000, which it says has now been repaid.

It brings the total amount repaid to $33,000, which is thought to be the total amount in membership fees paid by AWH to the NSW Liberal Party via the North Sydney Forum.

A NSW corruption inquiry into AWH has already claimed a ministerial casualty, with Liberal senator Arthur Sinodinos standing aside as Assistant Treasurer until the ICAC hearing has finished.

Senator Sinodinos was a director and chairman of AWH and he will appear as a witness.

He denies any wrongdoing and says he will “vindicated” after the ICAC heard he stood to gain up to $20 million from his involvement with AWH.

The inquiry has previously heard Mr Di Girolamo falsely invoiced Sydney Water for thousands of dollars in expenses and used the money for Liberal Party donations.

Senator Sinodinos will forgo his ministerial office and pay while he stands aside during the corruption inquiry.

Coalition figures insist the Senator has not been stood down from the ministry but has voluntarily stepped aside from the assistant treasurer’s job.

Prime Minister Tony Abbott has defended his colleague, describing him as a “brave man” who will return to the frontbench “soon”.