Federal police have raided the Sydney and Melbourne offices of Opposition Leader Bill Shorten's old union, the Australian Workers Union, as part of an investigation into donations made a decade ago to activist group GetUp!
The raids are linked to an investigation by the Registered Organisations Commission, which is also examining donations by the AWU to Labor campaigns in three seats at the 2007 election, including the seat of Maribyrnong, now held by Mr Shorten.
A spokesman for the Registered Organisations Commission said it received information which raised suspicions that documents relevant to the investigation at the AWU offices in Sydney and Victoria may be being concealed or destroyed.
The commission put the information to a magistrate who on Tuesday issued warrants under section 335K of the Fair Work (Registered Organisations) Act allowing documents to be seized from the AWU's national office in Sydney and the Victorian Branch office.
It is an offence to conceal, destroy or alter a document relating to an investigation being conducted, or about to be investigated by the Commission under Section 337AC of the act.
The unions said documents being sought by Australian Federal Police in the raids include minutes of an AWU national executive meeting.
The Turnbull government's newly established Registered Organisations Commission announced last Friday that it had begun investigating donations made by the AWU's National and Victorian offices.
"This afternoon, officers of the AFP executed these search warrants in Sydney and Melbourne on behalf of the ROC," the Commission spokesman said.
The raids came at the end of a day in which the Mr Shorten had led the opposition's attack on the Coalition in Parliament over inadequate funding and resources being made available to the federal police after a leaked internal documents revealed drug bust operations were under threat because of increased security needs.
The government furiously pushed back against this suggestion in question time.
The AWU's rules state that donations of more than $1000 must be approved by the national executive of the union.
The donations being examined include $100,000 paid by the AWU national office to Getup! in 2005-06*, and $25,000 paid by the AWU national office to Mr Shorten's campaign for the seat of Maribyrnong in 2005-06.
Two other donations to Labor campaigns - $20,000 in the WA seat of Stirling and $25,000 in the Queensland seat of Petrie - were made by the AWU in that same election and are being examined.
Mr Shorten was head of the AWU from 2001 until August 2007 and a former founding director of GetUp!
The raids on the offices of Mr Shorten's former union and the question marks over the donations will create a new headache for the opposition leader over his union past, which was examined in close detail by the Heydon royal commission.
Australian Workers Union national secretary Daniel Walton said the raids were "an extraordinary abuse of police resources and taxpayer funds by a desperate government".
Union lawyers on Tuesday afternoon were sent to the Melbourne Magistrates Court to object to the way the investigation was being handled.
Union officials said 26 AFP officers had been involved in Tuesday's raids on the AWU offices.
Both Mr Walton and Labor employment spokesman Brendan O'Connor raised concerns that media had been tipped off about the raids before they had taken place.
"It's a concern to us that before we find out they were planning to take this step, that we have media crews lined up outside the union offices," Mr Walton said. He said the union believed the Registered Organisations Commission's investigation and raids were politically motivated and designed to attack the reputation of Mr Shorten.
"Our union has been operating for 131 years," Mr Walton said, "but the Registered Organisations Commission has decided to look into a period that remains exclusively with Bill Shorten's time as secretary of the AWU."
Australian Council of Trade Unions secretary Sally McManus accused the Turnbull government of a "shocking attack on democracy".
Ms McManus dubbed the raids a "total and utter" waste of money, adding she was "totally confident there was nothing to worry about."
"The AWU is not concerned one little bit," she told the ABC on Tuesday night.
"We believe everything is absolutely above board, what we're concerned about, is [federal] police officers crawling through union offices."
A spokesman for the Australian Federal Police confirmed it was executing search warrants in Melbourne and Sydney in support of the Registered Organisations Commission in support of an ongoing investigation it was conducting.
Mr O'Connor accused Prime Minister Malcolm Turnbull and the Coalition of directing the Commission to start a "witch hunt" and said the government must explain what it knew about the raids.
"It's clear that Malcolm Turnbull has intervened and abused his position of power and abused the resources of the police to make an attack on the Leader of the Opposition," he said.
"Malcolm Turnbull clearly has misused the police. Today we discovered through Senate estimates that there are resource issues with the federal police...at the same time, we have a situation where the government is treating the police as its play thing, using the police to investigate a civil matter," Mr O'Connor said.
He did not provide evidence to support the claim of government intervention in police operations.
A government spokesman said the federal police were independent of government and that "Labor is attacking the independence, integrity and professionalism of the AFP and its officers. This is an offensive slur and a disgraceful distraction."
Employment Minister Michaelia Cash referred the donations to the Commission back in August.
- *An earlier version of this story incorrectly said the $100,000 payment by AWU to Getup! being examined was in 2007-08.
