Zimbabwe's upper house of parliament has approved controversial legislation that critics say will muffle civil society groups, placing them under the threat of harsh sanctions and strict government control.

The senate voted late Wednesday in favour of the Private Voluntary Organisations Amendment Bill, which needs to be ratified by the president before passing into law.

The bill bans civil society organisations from engaging in politics and allows the state to interfere in their governance and activities, such as make changes to their internal management and funding.

Those found in breach of its provisions risk up to a year in jail and the closure of their organisation.

Critics argue that its broad scope risks de facto criminalising the activity of any organisation disliked by the government.

"This is the lowest any modern state can get to. Especially a state that was born through struggle for freedom, independence and democracy," said Peter Mutasa, director of the Crisis in Zimbabwe Coalition, a civil society umbrella group.

Rights groups and opposition parties complain of an increased government clampdown on dissent as the country heads towards general elections later this year.

"The bill was long overdue and it brings sanity in the NGO sector who sometimes interfere with our politics," Pupurai Togarepi, the chief whip of the ruling Zanu FP party, said in December after the bill was approved by the lower house of parliament.