Senator Arthur Sinodinos has defended his salary as a company director and pleaded ignorance to numerous Liberal Party donations at the Independent Commission Against Corruption (ICAC) on Thursday.

The ICAC is probing allegations of corruption at Australian Water Holdings (AWH), the company at which the Senator served as director then chairman for four years from 2008.

While under intense questioning from counsel assisting the ICAC, Geoffrey Watson SC, Senator Sinodinos denied any knowledge of the $75,000 in donations paid by AWH to the NSW Liberal Party while he was a board member.

When Mr Watson questioned whether it was fair for Sinodinos to earn $200,000 a year for less than 45 hours work, the Senator defend himself by asking whether travel time had been factored in.

”Should we add on 90 seconds over a gin and tonic to the other 45 hours a year,” Mr Watson replied.

For hours, Sinodinos met the barrister’s barrage of cross examination with the excuse of a blank memory.

“I did not know in precise terms what was being donated to the Liberal Party, “ Senator Sinodinos told (ICAC) in Sydney.

When asked what he meant by “precise terms,” Sinodinos said: “I couldn’t quote amounts at you, or over what period.”

Mr Sinodinos denies any conflict of interest between his dual roles at the NSW Liberal Party and the AWH board of directors.

“Are you denying knowing that the company of which you were a director and deputy chairman was donating to a party of which you were the treasurer?’’ counsel assisting Geoffrey Watson SC asked.

“Yes,’’ Senator Sinodinos replied.

The allegations directed at the Senator are that he was hired by AWH to leverage his Liberal contacts, and that he did (or should have) known about extensive donations to the NSW Liberal Party and its associates.

Sinodinos told ICAC on Thursday that the matter of donations were never raised at AWH board meetings, and were a matter for lower level management.

The Senator did admit that while on the board he failed to investigate why costs at the company blew out from an anticipated $200,000 a month to, at times, $800,000.

“You did nothing to ascertain the facts behind the escalation of Australian Water Holding’s costs. Just answer the question,’’ Mr Watson said.

“Not specifically, no,’’ Senator Sinodinos said.

Sinodinos has voluntarily stepped down as assistant treasurer in the Abbott government until the ICAC inquiry is resolved.