Russia's highest court has given the green light to holding next year's parliamentary vote several months earlier.

Lawmakers in the Kremlin-controlled parliament in June gave tentative approval to a bill that would move up next year's vote by three months, a tactic that has been decried as an attempt to weaken the opposition.

The Constitutional Court ruled on Wednesday that holding the election three months earlier does not contradict Russia's constitution.

The ruling cleared the final hurdle for the parliament to move the 2016 election from December to mid-September. It would likely result in a lower public interest in the campaign, as many Russians go on vacation in the summer, and benefit the ruling party which tends to garner more votes when the turnout is low.