The New South Wales corruption watchdog is looking into allegations of dodgy payments from construction companies to an engineer at a state-owned energy utility.

Former Ausgrid engineer Phillip Cresnar is being investigated by the NSW corruption watchdog over claims he received kickbacks from contractors during a six-year period from 2008 to 2014.

Mr Cresnar allegedly solicited and received benefits from Ausgrid contractors and subcontractors, who paid for assistance with the awarding contracts and some variations to contract terms.

The NSW Independent Commission Against Corruption is moving on claims that Mr Cresnar gave out confidential information acquired in the course of his official functions, according to an ICAC statement.

The inquiry starts on January 19.