Venezuela's lame duck congress approved the appointment of 13 Supreme Court justices Wednesday in a move that the opposition said is meant to undermine its landslide victory in this month's legislative elections.

The government-controlled National Assembly approved the candidates on a simple majority vote after failing to win passage by a two-thirds vote in three previous efforts.

Assembly President Diosdado Cabello said the final approval was in accordance with the constitution, while the opposition said the lack of a two-thirds majority approval constituted a "legislative coup."

The appointments fill vacancies left by justices who retired early rather than let opposition lawmakers affect the makeup of the staunchly pro-government high court.

Opposition candidates won 112 of the assembly's 167 seats in elections this month, giving them power to challenge the socialist administration of President Nicolas Maduro. They won't take office until January.