Russia's parliament has approved former President Dmitry Medvedev as prime minister with a vote of 299-144.

He will serve under Vladimir Putin, the former prime minister who began a third presidential term on Monday.

As promised when the two men announced in September that they intended to swap jobs, Putin wasted no time in formally nominating his junior partner for the government post.

Parliament had to formally approve the nomination, but the result was never in doubt since the Kremlin party holds a majority of the 450 seats.

Putin spoke to parliament ahead of Tuesday's vote and asked lawmakers to approve the man he described as an "experienced politician" who "sincerely loves his motherland."