Malaysian authorities on Friday sealed off parts of a public square where activists plan to stage a high-profile rally demanding more transparency in upcoming general elections.

Thousands of people are expected to gather Saturday near Kuala Lumpur's Independence Square to seek sweeping changes in polling regulations. The planned rally is part of a push by an opposition-backed group to curb fears of fraud in elections that many speculate will be held in June.

An estimated 20,000 people marched to make similar demands in July. Police used tear gas and water cannons to break up that rally and briefly arrested about 1,600 demonstrators.

The organizers of Saturday's rally insist that voter registration lists are marred by manipulation and that the Election Commission is biased. They also want changes to ensure that citizens living abroad can cast ballots, as well as international observers for the polls and fairer access for all political parties to the government-linked media.

Prime Minister Najib Razak has insisted Malaysia's current laws are sufficient to prevent electoral irregularities. Electoral authorities say the activists' other accusations are unsubstantiated.

City officials placed plastic and steel barricades around Independence Square on Friday after warning that demonstrators had not obtained legal consent to use the area.

Home Minister Hishammuddin Hussein said late Thursday that the government was willing to allow a rally at an "appropriate and lawful venue" to maintain security and public order.

Officials have proposed several stadiums for the rally, but organizers say it's too late to switch locations.

The organizers have linked up with supporters and rights groups worldwide to stage small-scale demonstrations in major cities in Asia, Australia, Europe and the United States on Saturday.

The planned rally comes amid intense speculation that Najib might dissolve Parliament next month and seek a new mandate in June, even though polls do not need to be held until mid-2013. The prime minister has refused to confirm the rumors.

The National Front, which has governed Malaysia since independence from Britain in 1957, suffered its worst performance in 2008 elections, when it lost more than a third of Parliament's seats amid public discontent over problems such as corruption and racial discrimination.