President Paul Biya is set to get a vice-president for the first time in his four-decade rule following controversial constitutional changes backed by parliament.

The position was scrapped in 1972.

In recent years, the leader of the Senate was expected to act as president, but only until a fresh election was arranged.

Biya is expected to sign the widely criticized bill into law after it was approved in a joint session of the National Assembly and Senate and boycotted by the main opposition party; 200 votes were cast in favor, 18 against, and four abstained.

In the new amendment, the aging president has absolute control over the vice president's office, as he has the power to appoint and dismiss him at will, while his deputy can only exercise those powers that have been delegated by Biya. If the president dies, resigns, or becomes incapacitated, the vice president will act as interim president.Biya has ruled the oil and cocoa-producing nation since 1982.

The opposition said the amendments were hastily drafted and aimed at consolidating power.

The world's oldest serving leader won an eighth term in power last October with 53.7% of the vote in an election that the opposition said was rigged.