A construction boss felt "held at ransom" by an ex-Ausgrid engineer who allegedly demanded expensive gifts in return for help securing government contracts, the ICAC has heard.

The NSW Independent Commission Against Corruption is investigating allegations Phillip Cresnar solicited and received more than $300,000 in kickbacks between 2008 and 2014 from companies vying for work laying electricity cables.

As a project engineer for the state-owned Ausgrid, Mr Cresnar initiated and helped oversee contracts in Sydney’s northern suburbs worth millions of dollars, the inquiry heard.

He allegedly used the kickbacks to pay for renovations to his inner-Sydney home and work on his luxury car, along with electronics, tickets and appliances.

ICAC heard one company, Bastow Civil Constructions, supplied $67,000 in gifts via a company credit card between 2008 and 2010, and paid for $25,000 work on Mr Cresnar’s Saab with a company cheque.

Director Jason Bastow told the inquiry he hesitated when Mr Cresnar initially asked for certain household items, but eventually paid up.

He said he feared jobs for his company would dry up should kickbacks cease.

“It was like I was held at ransom in some respects,” Mr Bastow said.

At one point, ICAC heard, a Bastow Civil company credit card was linked to Mr Cresnar’s PayPal account and used for $36,500 worth of transactions.

Mr Bastow told the inquiry he did not authorise the linkage and confronted Mr Cresnar after his wife discovered what was going on while checking the accounts.

His company completed Ausgrid contracts worth $20 million between 2007 and 2012, the greatest proportion of which were awarded during the two years in which kickbacks were paid to Mr Cresnar.

The directors of another contractor, Murray Civil Works, allegedly funded expensive renovations to Mr Cresnar’s Alexandria home in 2012 and 2013.

These included $15,000 marble tiles, a $22,000 wall unit, a $5700 fireplace, plus a marble bath and two toilets worth about $7800.

Murray Civil Works completed more than $26 million worth of Ausgrid contacts between 2011 and 2013 – most after Mr Cresnar’s long-time friend, Denis Twomey, was appointed director.

It’s alleged Mr Cresnar received further benefits from several sub-contractors, including airfares.

An anonymous source blew the whistle on Mr Cresnar in 2013 and the engineer was fired in 2014.

He is the subject of an ICAC inquiry because he was a public official while employed by Ausgrid.

The inquiry is expected to run for four more days.