Health Services Union national president Michael Williamson has resigned via text message after damning allegations of nepotism at the scandal-hit union.

Acting HSU national president Chris Brown has confirmed he received the text message tendering Mr Williamson's resignation on Monday.

It comes less than two weeks after a leaked report into the union's internal workings alleged that Mr Williamson engaged in nepotism while he was general secretary of the branch.

Mr Williamson stood aside last September when investigations into allegations of misuse of funds in the union's East branch began, though he still formally held the position.

Mr Brown says Mr Williamson resigned ahead of a national executive committee meeting in Sydney yesterday.

"He'd advised me by text so I have not yet had an opportunity to speak to Michael Williamson but I've taken the resignation as being effective immediately," he said.

"It's another piece of [what] we needed to occur to clean up the union and get it to the stage where members could get back to having confidence in it.

"What we'll be able to do now is fill that position of national president."

Mr Williamson has previously declined to comment about the Temby report, and was not interviewed by its authors.

The leaked report, authored by barrister Ian Temby QC and accountant Dennis Robertson, paints a picture of a union with lax internal controls which had scant concern for its members' funds.

It details salaries for Mr Williamson of almost $400,000, and $287,000 for its secretary Kathy Jackson.

The report found the salary was not the only income Mr Williamson received from the union.

The union contracted a company belonging to him to provide IT services, and the report suggests the union was its only customer.

It was paid nearly $4.7 million from 2008 to 2011, and was located rent-free at the union's offices in Sydney.

The report also alleges that five members of Mr Williamson's family were among the union's best paid employees.

It claimed his wife was given $350,000 to scan documents over a three-and-a-half year period.

The report also alleges a warehouse in Sydney, which was bought with union funds, appears to have been converted in to a recording studio to be used by Mr Williamson's son for commercial benefit.

The report does not mention the former national secretary, Craig Thomson, except to say that he was seen as Mr Williamson's protégé.

Earlier this year Mr Thomson was suspended from the Labor Party's caucus over the allegations that he misused union funds while at the national branch of the HSU, allegations he denies.

HSU East is now in administration.