Two 8-year-old girls in Thailand have been charged for tearing down voter lists off a wall ahead of an upcoming referendum, police said on Sunday.

The military government has tightened on the disagreement ahead of the August 7 vote on a military-backed constitution. They say that it will ensure stability in the country which is going through a rough phase of political turmoil for more than a decade.

Damrong Phetpong, police commander in the northern province of Kamphaeng Phet said the girls were charged for violating campaigning rules and obstructing the referendum process. They were also charged of destroying public property by tearing down the lists which were posted outside a school.

"They confessed to tearing down the voter lists because they liked the colour pink," Damrong told Reuters.

Damrong added that they would not face punishment as they were too young.

Since the military seized power in May 2014, this referendum will be the first time when Thailand will go to the polls. The ruling government has said that the referendum will pave the way for an election next year.

Critics, including the major political parties, said that the Constitution will preserve a political role for the military and weaken civilian governments.