The office of a former Victorian Labor powerbroker misappropriated up to $14,000 and paid his father for cleaning services never provided, an anti-corruption inquiry has heard.

Former staffer Adam Sullivan told the Independent Broad-based Anti-corruption Commission he spent up to $14,000 from Adem Somyurek's electorate office budget on stamps for Mordialloc MP Tim Richardson's 2018 re-election campaign.

Mr Sullivan said he was told in early 2018 by Nick McLennan, a ministerial adviser to Koroit MP Marlene Kairouz, to purchase the stamps using the budget, which is not meant for political purposes.

"It was suggested that the purchase of these stamps take place in increments, nothing that would be conspicuous to the department of parliamentary services," he said on Wednesday.

Mr Sullivan said he purchased the stamps, which were then passed on to Mr Richardson's campaign.

He said although Mr Somyurek didn't personally ask him to buy the stamps, it "didn't seem like it was the sort of thing that would be frowned upon" by the MP.

Mr Sullivan also told the inquiry Mr Somyurek's father was paid for cleaning services despite the office being "decrepit", "rundown" and "complete with cobwebs".

"There were also cockroaches in the kitchen when I first arrived there so I made sure we got an exterminator," he said.

Mr Sullivan said he never saw anyone clean other than himself, and that it was not "common practice" for family members of an MP or factional ally to be employed in electorate offices.

He said four other staffers worked at the office, including a woman employed as a casual for six weeks full-time but he rarely saw.

Mr Sullivan only saw Mr Somyurek once at the office in the nine months he worked there.

Prior to working as an electorate officer for Mr Somyurek, Mr Sullivan worked for his moderate faction ally, federal MP Anthony Byrne.

There, he would handle "wads of cash", given to him by MPs and aspiring MPs to pay for or renew other people's Labor memberships.

Mr Sullivan also conceded there was a risk dead people could have had their Labor memberships renewed in the operation, but did not admit to doing it himself.

These memberships helped the faction gain influence in Melbourne's southeast and ensure their preferred candidates were preselected.

The practice, known as branch stacking, is not illegal but is against Labor party rules. IBAC is investigating whether public funds were used for such work.

Mr Sullivan's testimony comes after Mr Somyurek's former executive assistant Ellen Schreiber told the inquiry on Tuesday she spent up "80 per cent" of her workday dealing with memberships.

This included attending internal Labor party committee meetings along with Mr Sullivan and another man, Oscar Goodwin, to approve memberships.

Mr Sullivan said the committee was up to 75 per cent comprised of electoral officers.

"It's not on paper that this would be a part of your job, but if you didn't do (it) you wouldn't have a job essentially," he said.

He said no one blew the whistle on the behaviour because it would have meant "mutually assured destruction".

Mr Sullivan, who has also worked for Ms Kairouz and upper house MP Tien Kieu, said he joined Labor to make a difference but now feels ashamed of his actions.

Mr Somyurek quit the Labor Party in June 2020 after allegations of branch stacking first surfaced, while Ms Kairouz resigned from cabinet but remains on the government backbench. Both deny any wrongdoing.

The IBAC hearings will resume on Monday.