Mr Joyce, who is also the Resources Minister, missed a media event on Monday where the government demanded NSW accelerate approval of the Santos project at Narrabri, north-west of Sydney, to ease a looming gas shortage. He lists land at Gwabegar, west of Narrabri as part of his pecuniary interests.

While Mr Joyce said on Tuesday there is no prospect of gas being extracted on his land, local activists opposed to coal seam gas development say petroleum exploration licences all through the region depend on progress at Narrabri.

The Nationals leader bought two blocks of about 1000 hectares in "mongrel country" of poor economic value in 2006 and 2008 for a reported $572,000.

In 2013, he told Fairfax Media he understood the ownership could be "viewed as a conflict of interest", but denied knowing the region potentially held CSG reserves until years after the purchase.

That lack of knowledge was despite Mr Joyce's close ties to John Anderson, the former Nationals leader, who became chairman of Eastern Star Gas in 2007. Eastern Star co-owned explorations rights to a nearby area - PEL 428 - before the company was taken over by Santos.

On Tuesday, the Deputy PM hit the air waves promoting the need to develop the multibillion-dollar Santos project, despite the federal government-appointed independent expert scientific committee recently finding significant "knowledge gaps" in the environmental impact study put forward by the company.

Mr Joyce's office declined to say what he was asking for the properties, which have reportedly been on the market for years. Mr Joyce has said he would not make a "windfall" on the land.

Mr Joyce acknowledged the issue of his property ownership on Fairfax Media's 2GB radio this morning.

"I've got a property probably maybe 30 or 50 kilometres from [the Narrabri CSG field]," Mr Joyce said. "And there's no gas being extracted on my place."

"[There's] no prospect of it," he said. "And there's nothing for me to earn from it."

A spokesman for Mr Joyce said the property had not had a single offer and he has not set an asking price.

"There has never been a single person ever set foot on the properties to explore for gas or any other resource," the spokesman said.

But Peter Small, a spokesman for the North West Alliance of 30 groups apposed to CSG development in the area, said Mr Joyce should not be making public speeches about Narrabri when he stood to benefit.

"We still see it as a conflict of interest," Mr Small said.

Santos hold petroleum exploration licences in the region, including around Mr Joyce's property, all of which depended on the Narrabri project proceeding.

The Narrabri project, 60 per cent of which sits in the Pilliga state forest and the rest farmland, is merely "stage one" of the development of CSG in the region.

"Without that stage one, [Mr Joyce] stands to gain nothing," Mr Small said.

About a dozen exploration licences still stretch from Moree down to Dubbo, with the region near Gwabegar likely "the next in line", he said.

Tony Windsor, who lost a bitterly fought election against Mr Joyce for the seat of New England in 2016, said it was well known "there'd be gas under all that country".

Mr Windsor, who is also challenging Mr Joyce in the High Court over the Deputy PM's status as a New Zealand citizen when elected, said the Gwabegar area was "useless country".

"You'd wonder how you could make fifty bucks from it," with harvesting feral goats among its most lucrative prospects, Mr Windsor said.

A spokesman for Don Harwin, the NSW energy minister, said Santos remains the holder of the exploration licences - 428 and 238 - near Mr Joyce's land holdings.

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