Russia's lower house on Wednesday passed constitutional reforms in their final reading that include the possibility of President Vladimir Putin extending his rule for another two terms.

A total of 383 State Duma lawmakers voted in favour of the package of constitutional amendments, with 43 abstentions and none against.

The measures must now be approved by the upper house Federation Council and be put to a public vote scheduled for April 22.

Putin announced the package of reforms in January, then repeatedly denied they were meant to extend his grip on power as he approaches the end of his fourth and final presidential term in 2024.

However, on Tuesday another amendment was introduced that would reset presidential terms, making it possible for Putin to run again if the constitutional court allows it.

The changes "are not just justified... they plan... for the strategy of the development of the country," Duma speaker Vyacheslav Volodin said after Wednesday's vote, Russian agencies reported.

Other additions to the constitution include guarantees for pension payouts and minimum salaries, and giving parliament additional power to nominate the head of government. 

They also give the president additional powers to fire judges in the country's higher courts and to reject laws passed by parliament.