The polls are expected within weeks and Prime Minister Najib Razak is battling to keep his long-ruling coalition in power despite allegations that billions of dollars were looted from a sovereign wealth fund founded by him.
The electoral constituency bill was due to be tabled in parliament Wednesday, two days after the government proposed a law to combat "fake news" carrying a maximum 10-year jail term, that critics said was aimed at stifling dissent.
Electoral authorities say redrawing boundaries is a regular exercise that must be undertaken to reflect demographic changes.
However the ruling Barisan Nasional (BN) coalition, which has been in power since independence in 1957, has long been accused of rigging the electoral map to help it in polls, and the plan sparked accusations of gerrymandering.
About 200 protesters marched on parliament, waving signs that read "stealing an election is not winning an election" and "we will not be silenced".
"We believe an election victory may be stolen from us."
The opposition alleges that the plan to redraw boundaries will see voters who traditionally favour them lumped together in larger constituencies, creating smaller constituencies packed with pro-BN voters -- particularly the country's Muslim Malay majority.
But Abdul Rahman Dahlan, minister in charge of economic planning, denied the claims.
"Each time the redrawing of constituencies is done, the opposition cries foul," he told AFP.
The bill needs to be backed by a majority of MPs to pass and is expected to do so as BN has most seats in the 222-seat parliament.
Despite the scandal surrounding state fund 1MDB, Najib is tipped to win another parliamentary term due to alleged vote-rigging and his coalition's strong grip on the electoral machinery.
He is however facing a strong challenge from the opposition's candidate, veteran ex-leader Mahathir Mohamad, 92, who is still popular with rural voters.
(Except for the headline, this story has not been edited by NDTV staff and is published from a syndicated feed.)