There are 39,865 registered voters in the constituency.

The 19 polling centres will close at 5pm and the results are expected to be announced before 10pm.

At a press conference, Sabah police commissioner Omar Mammah said police had received 12 reports on alleged irregularities in the by-election.

He said police have opened six investigation papers and closed four cases.

Omar said the latest investigation paper was opened after police received a report of alleged attempts by candidates to buy votes.

“The report was lodged at 12.06am today stating that there were certain parties giving out money to voters.

“We have begun investigations under Section 10 of the Election Offences Act,” he said.

He said police issued a total of 362 permits for activities during the two-week campaign period.

Omar also dismissed rumours and fake news that security was at an all-time low to discourage voters from coming out.

“We have dispatched a total of 874 police personnel today and also heightened security at border islands to guarantee the people’s safety.

“I advise the public not to fall for these rumours. Rest assured, we will take action against those who continue to spread fake news,” he said.

DAP’s Vivian Wong is attempting to defend her late father’s seat against Parti Bersatu Sabah’s (PBS) Linda Tsen and three independent candidates — Hamzah Abdullah, Chia Siew Yong and Sulaiman Abdul Samad in the by-election.