Israeli lawmakers approved on Monday a key clause of a controversial judicial reform plan that aims to curb the powers of the Supreme Court in striking down government decisions.

The text was approved by all 64 lawmakers from the ruling hard-right coalition of Prime Minister Benjamin Netanyahu, with opposition MPs boycotting the vote.

The vote reflected the determination of Netanyahu and his far-right allies to move ahead with the plan, despite massive, sustained protests for months and opposition from business leaders, military reservists and legal officials.

In Monday's vote, lawmakers approved a measure that prevents judges from striking down government decisions on the basis that they are "unreasonable."

Proponents say the current "reasonability" standard gives unelected judges excessive powers over decision-making by elected officials.

However, critics of the government says it removes a key element of the court's oversight powers and opens the way for corruption and improper appointments.

After the vote, Justice Minister Yariv Levin, the architect of the plan, said parliament had taken the "first step in an important historic process" of overhauling the judiciary.

More mass protests were expected after the vote.