Wellington, March 17 NZPA - The jury retired this afternoon to consider its verdicts in the trial of three men accused of breaking into and damaging the Waihopai spy base near Blenheim.

Adrian Leason, a teacher, Dominican friar Peter Murnane and farmer Sam Land have pleaded not guilty in Wellington District Court to one count of burglary and two of wilful damage at the Government Communications Security Bureau (GCSB) facility.

The prosecution said the trio cut their way through fences into the base, then slashed the plastic cover over a satellite dish with sickles.

In his closing arguments today, Leason's lawyer Michael Knowles said the men were driven by a belief that the satellite caused human suffering and their actions to shut it down, if only temporarily, were lawful.

"That belief doesn't have to be correct," he said.

"They had a belief in a higher law, a law for protecting people."

Murnane, who defended himself, said he believed the satellite aided crimes against humanity.

"I had to do this, it was necessary for me," he said.

Land's lawyer, Tony Shaw, said his client genuinely believed his actions were lawful, and he should be acquitted.

Crown prosecutor Glen Marshall said the men deliberately and intentionally damaged the satellite cover hoping, rather than believing, their actions were lawful.

"It's not a belief, it's something less, a hope, an expectation, an opportunity," he said.