Shyster, fraudster, liar: ex-Australian Water Holdings boss Nick Di Girolamo has endured a string of barbs during a long day in the ICAC witness box.

Embattled Liberal identity Nick Di Girolamo was accused of creating sham documents, giving false testimony and making up evidence at the corruption watchdog on Monday.

But counsel assisting the NSW Independent Commission Against Corruption (ICAC), Geoffrey Watson SC, waited until the final 45 seconds of the day to land his body blow.

“Aren’t you just an old-fashioned shyster fraudster, Mr Di Girolamo? Isn’t that the case?” he asked.

Mr Watson had just accused the former Australian Water Holdings (AWH) chief executive of including a “bare-faced lie” about AWH’s worth in a pitch to the NSW government for a lucrative public-private partnership.

“The answer to your question is no,” Mr Di Girolamo replied from the witness box.

The ICAC has entered the final week of a long-running investigation into AWH and allegations it corruptly billed Sydney Water for lavish salaries and luxury travel.

Mr Di Girolamo, a prominent Liberal fundraiser, has admitted “mistakes” were made but denied big-noting himself at the utility’s expense with a series of extravagant lunches, limousine trips and big donations.

The inquiry has previously heard he went over former NSW Liberal frontbencher Greg Pearce’s head to arrange a “cosy” meeting with Premier Barry O’Farrell, who will face the inquiry on Tuesday.

It has also been alleged the family of crooked ex-MP Eddie Obeid had a secret stake in AWH and stood to make up to $60 million if the company’s proposal for a public-private partnership was successful.

Mr Di Girolamo – a former managing partner at law firm Colin Biggers & Paisley – appeared to contradict himself over details of a controversial deal with members of the Obeid family.

The Obeids have insisted they were lending Mr Di Girolamo $3 million despite the heading “Sale of Shares” in a November 2010 contract and the listing of Mr Di Girolamo as the “vendor”.

“You’re saying that you think it could be a loan despite the fact that there was no reference to a borrower, no reference to a lender, no reference to a principal, no reference to a repayment date, no reference to a debt and not even a reference to a loan?” Mr Watson asked incredulously.

“You’re telling us that as an experienced lawyer you still signed the document believing that to be the fact, are you?”

“Yes,” came the reply.

Mr Watson has told the inquiry the agreement really records the Obeid family’s purchase of AWH shares, but Mr Di Girolamo denied the family ever had a significant stake in the firm.

“You and (Eddie Obeid Junior) set out to try and trick ICAC didn’t you, you tried to provide sham documents and false testimony in respect of the Obeid family ownership of the company, didn’t you?” Mr Watson said, to strident denials from Mr Di Girolamo.

He will continue giving evidence on Tuesday.