An anti-fracking activist has been found guilty of trespass after entering a Buru Energy drilling compound to film evidence of a methane leak at one of its wells.

Key points: Activist admits entering Buru Energy's compound near Broome

Activist admits entering Buru Energy's compound near Broome Says he was worried about leaking gas at a well there and wanted to film it

Says he was worried about leaking gas at a well there and wanted to film it Pleaded not guilty on the grounds of public health concerns

Pleaded not guilty on the grounds of public health concerns Found guilty of trespass, magistrate accepted his concern was genuine

Found guilty of trespass, magistrate accepted his concern was genuine Department of Mines and Petroleum says monitoring adequate for well

Broome man Damien Hirsch, 44, admitted to entering the compound in 2014, but pleaded not guilty to trespass on the grounds that public health concerns warranted the action.

The footage showed a handheld meter apparently recording dangerously high levels of methane being released from the Yulleroo 2 gas well, 70 kilometres east of Broome.

Magistrate Stephen Sharratt found Hirsch guilty of trespass, but accepted he was genuinely concerned about inaction over the gas leak.

"I accept the valve was leaking to the extent it could be heard and smelt," he said.

He said Mr Hirsch "wanted to show the department's inaction ... and committed trespass to gather evidence".

"His motives were good, but jumping into the compound was not trivial ... it was dangerous, he took a great risk, he could have been blown up," Mr Sharratt said.

He said acquitting him would set a precedent that would see "people committing trespass all over the state" when concerned about environmental issues.

During the trial, the court heard evidence the then-Department of Environment and Conservation passed on concerns about a gas leak at the well as far back as 2013, but the Department of Mining and Petroleum (DMP) response was minimal.

Leak concern raised in 2013 with government department

Manager of Critical Risk at DMP, Shane Daniel, who was responsible for investigating the leak following the broadcast of the footage, said he did not know when the Yulleroo fracking well was last inspected, despite regular safety checks being required as part of Buru Energy's exploration permit.

Mr Daniel said while he had only been employed by the department for a short time, he understood monitoring practices had been haphazard, but they had since improved.

The issue of what caused the gas leak remains controversial.

Last year in State Parliament, Mines Minister Bill Marmion accused anti-fracking campaigners of deliberately sabotaging the valve, saying only a heavy instrument like a sledgehammer could have caused the damage.

The accusation was angrily rejected by Broome-based anti-fracking campaigners.

In his sentencing comments, Magistrate Sharratt agreed that "there is evidence it leaked because of tampering", but stopped short of suggesting who may be responsible.

A police investigation into the leak has not resulted in any charges being laid.

Speaking outside the court, Mr Hirsch said he felt vindicated by Magistrate Sharratt's comments.

"It has certainly shown that the Department of Mines and Petroleum was unable - and unwilling perhaps - to properly monitor this well," he said.

"It's not safe for the people and the animals and the water."

In a statement, Department of Mines and Petroleum Executive Director Petroleum Jeff Haworth said once the department was informed of the issue, and Buru's remedial process to replace the grease nipple was completed, they were satisfied the issue of the leak had been resolved.

"When DMP inspectors attended the site, there was no evidence of a gas leak until the valve was manipulated," he said.

"DMP inspectors attended the site immediately after it was alerted by the media that a gas leak had been reported in January 2015.

"The department is confident its current monitoring practices are adequate for inactive and suspended wells such as Yulleroo 2."

Buru Energy has been contacted for comment.