Wellington, March 17 NZPA - Three men have been found not guilty of breaking into and damaging the Waihopai spy base near Blenheim.

Adrian Leason, a teacher, Dominican friar Peter Murnane and farmer Sam Land were cleared of all charges after a two hour retirement by a jury at Wellington Diostrict late this afternoon.

The trio had pleaded not guilty to burglary and 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.

Lawyers admitted the men attacked the base but said they 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," one said.