BANGKOK (AFP) - A gang of 100 marauding monkeys have become the latest saboteurs to target a referendum trumpeted by the Thai junta as a cure for the nation's political crisis, after they tore down voter lists.

The primate rampage comes days after police charged two eight-year-old girls for ripping down voter lists elsewhere in the country, in a legal move that sparked incredulity.

The junta is going to increasingly bizarre lengths to quash dissent before the August 7 plebiscite on a new constitution, which the generals say will end political turmoil.

Criticism of the draft charter is punishable by up to 10 years in jail under a special law, a move which rights groups say has turned the vote into a sham.

Many activists see the charter as an attempt to perpetuate the military's grip on power.

A series of ripped voter lists at polling stations around the country over the past week have strained the nerves of authorities, although the eight-year-olds are too young to face jail.

On Monday officials were forced to pin up new lists in the northern province of Phichit after around 100 macaque monkeys left the documents in tatters.

"They are naughty animals so they tore it down," Prayoon Chakpacharakul, the director of the province's election commission, told AFP.

News of the monkey business inspired social media wags, with some joking they were deployed by ex-premier Thaksin Shinawatra - the junta's nemesis.

A cartoon circulated on Facebook showed the self-exiled former premier feeding bananas to a troupe of monkeys as they gleefully tore into voter lists.