A senior minister in the Morrison government could face a formal inquiry into controversial meetings about critically endangered grasslands.
The government has so far managed to fend off an investigation into meetings between Energy Minister Angus Taylor and the environment department.
A Labor motion for an inquiry into the matter was defeated on Thursday after crossbenchers, including Rex Patrick from Centre Alliance, voted against it.
But after spending the weekend reading media reports and government documents about the land-clearing controversy known as "grassgate", Senator Patrick has changed his mind.
"I'm now satisfied there is a prima facie case that the minister has made representations when there was a personal interest involved," he told reporters in Adelaide on Sunday.
In its bid to prevent the inquiry, the government produced a letter that purported to show the minister was acting in the interests of his constituents and not himself.
However, the letter from the NSW Farmers Association was written nearly six months after the meetings were held.
"Unfortunately it turns out that letter was dated six months after the initial meeting between Angus Taylor and the department," Senator Patrick said.
"I am a bit disappointed myself that I didn't pick up on the dates last week ... I take responsibility for that."
Labor is pursuing the cabinet minister over his interest in a family company linked to an investigation into the alleged illegal land clearing.
Its pursuit centres on 2017 meetings with environment department officials and the office of then-environment minister Josh Frydenberg to discuss the grasslands' listing as endangered.
The meetings were held while investigations were underway into the alleged poisoning of 30 hectares that contained the grassland on a NSW property owned by Jam Land Pty Ltd.
Mr Taylor's brother Richard is one of Jam Land's directors, while their family investment company, Gufee, is a shareholder.
Mr Taylor says his interests have been widely declared and has accused Labor of launching a "grubby smear campaign".
The minister insists he was representing farmers in his electorate of Hume and the neighbouring seat of Eden-Monaro.
Mr Taylor has repeatedly stated he made no representations to federal or state officials about the illegal land-clearing investigation.
He also told parliament he didn't ask for or know an investigator from the federal department's compliance team attended the meeting.
