Activist group GetUp has been declared independent of any particular political party, after an investigation by electoral authorities.
The Australian Electoral Commission found, in a report released on Monday, that GetUp was not an "associated entity" at the time of the 2016 federal election.
The AEC said it had considered documents provided by Liberal MP Ben Morton, publicly available information, and material provided by GetUp, as well as advice from the Australian Government Solicitor and federal prosecutors.
GetUp national director Paul Oosting said it was the third time the commission had ruled in the organisation's favour, despite accusations by "hard right politicians".
"The hard right forced this expensive, two-year investigation on the GetUp movement, in the hope it would silence all one million of us. But it has done exactly the opposite," he said in a statement.
"You don't make our democracy stronger by penalising a grassroots organisation for talking to voters."
AEC first assistant commissioner Tim Courtney said in a cover letter with the report: "We have reached a conclusion that there is insufficient material and evidence to show that GetUp was an associated entity at the relevant time."
GetUp ran a number of high-profile campaigns in 2016-17 including Save the Reef, Our Clean Energy Future, Protect Medicare and Better Power.
The AEC found the fact that an organisation advocates an agenda on one side of the political spectrum does not mean it is "operating" for the benefit of all registered parties on that side of the spectrum.
Associated entities have a number of obligations, including lodging a public financial disclosure with the AEC.
They are more commonly organisations such as unions, "500 clubs" and think tanks.
Liberal senator Eric Abetz said GetUp was a "highly partisan, extreme left-wing front" set up with the support of Labor and unions.
"I will continue to expose GetUp's dubious, disappointing and hypocritical activities," he said in a statement.
