A former staffer of long-time Wollongong MP Noreen Hay has been found guilty of forging electoral roll documents ahead of Ms Hay's successful re-election to the New South Wales Parliament in 2015.

Susan Maree Greenhalgh was found guilty of five counts of using forged document for public official to accept as genuine.

The offences detail five Wollongong electoral enrolments, including names and addresses, being falsely and dishonestly lodged.

Magistrate Susan McGowan handed down the guilty verdict in Wollongong court on Monday.

Ms Hay, a long-standing Labor MP, held the seat of Wollongong from 2003 to 2016.

The Australian Federal Police (AFP) raided Ms Hay's offices on Crown Street, Wollongong in July 2015 and seized several documents.

The raid was prompted by a referral from the Australian Electoral Commission in December 2014 over enrolment fraud and misconduct.

Greenhalgh was a senior electorate officer of Ms Hay's for nine years and was charged as a result of the AFP investigation.

Allegations caused disruption in party

Ms Hay, a former union official, was the state Labor Party's whip until May 2016, but stood aside from the position pending the outcome of the investigation.

Noreen Hay was the Member for Wollongong from 2003 to 2016. ( Supplied: NSW Parliament )

She resigned from Parliament in September 2016 and has previously denied all knowledge of electoral fraud.

Then-Opposition leader Luke Foley threatened to resign as leader in May 2016 unless Ms Hay stood down.

The allegations against Ms Greenhalgh caused much division among the party, and Ms Hay did not nominate for the whip position again.

Ms Hay resigned after 13 years in the role, with her resignation believed to be because of health concerns.

At the time she described her service to Wollongong as an honour and a privilege.

Greenhalgh will be sentenced on July 3.