The Election Commission expects about an 80 percent turnout at the Kajang state constituency by-election here Sunday.

EC chairman Tan Sri Abdul Aziz Mohd Yusof said that as of 11 am, 12,288 or 32.29 percent of the 38,055 registered voters had cast their ballots.

The EC's observation of the polling centres which were open at 8 am found that voters and supporters from both parties were co-operating and obeying directions, he told reporters after surveying a centre at Sekolah Kebangsaan Seri Sekamat here today.

Fifteen polling centres are open until 5 pm for the by-election.

The by-election is a straight fight between the Barisan Nasional (BN) and Parti Keadilan Rakyat (PKR). The BN is represented by MCA vice-president Datin Paduka Chew Mei Fun and PKR, by its president Datuk Seri Dr Wan Azizah Wan Ismail.

The EC expects the results to be announced by 9 pm.

Abdul Aziz called on the political leaders to advise their supporters and party machineries present at the polling centres to be courteous and abide by the rules to ensure a smooth balloting process.

He also urged supporters from both sides to refrain from any provocation which could disrupt the process.

"The campaign period ended at midnight. Today the voters are here to choose their representative. They should not be disturbed any more," he said.