Labor and the Greens have demanded answers about a cabinet minister's meetings with the former environment minister over alleged illegal landclearing on a property partly owned by his family.
Angus Taylor met with Josh Frydenberg when he held the environment portfolio in relation to critically endangered grasslands at the centre of an investigation involving companies part-owned by Mr Taylor.
Mr Taylor, who is now energy minister but held a more junior frontbench role at the time, met with Mr Frydenberg about the protection of the natural temperate grassland of the south-eastern highlands in 2017.
The meetings were held while investigations were under way into the alleged poisoning of 30 hectares that contained the grassland on a NSW property owned by Jam Land Pty Ltd.
One of Jam Land's directors is the minister's brother Richard Taylor, while the minister's family investment company, Gufee, is a shareholder in Jam Land.
Greens senator Larissa Waters questioned how a meeting to see whether the listing of an endangered grassland could be weakened or modified could be justified.
"Clearly there's something fishy going on here and the public are sick of it, we're sick of it," Senator Waters told parliament.
"Ministers shouldn't be able to put their own personal financial interests ahead of the interests of Australians."
In a brief statement to parliament, Government Senate leader Mathias Cormann said Mr Taylor had disclosed his interests in line with the statement of ministerial standards.
"Minister Taylor has repeatedly made clear that he has made no representation in relation to his family company to any federal or state ministers, or to any federal or state departmental officials," he said.
Mr Taylor has previously said he received a briefing in his capacity as the local member for Hume and the compliance action was not discussed.
But Labor senator Jenny McAllister argued the grassland was almost entirely outside his electorate.
"This episode looks like the absolute worst of what people fear about this government," she said.
"Insiders using a private position to help themselves and their families, ministers using their considerable power for what appears to be personal gain."
The Greens' push for Mr Taylor and Mr Frydenberg to be included in a ministerial standards inquiry involving former defence minister Christopher Pyne and former foreign minister Julie Bishop was defeated on Monday.
Australian Associated Press