Ballot papers and other documents used in the Punggol East by-election will be destroyed next week, in accordance with the Parliamentary Elections Act, the Elections Department said on Friday.
The papers have been kept in sealed boxes and stored in the Supreme Court since the election took place in January. They will now be destroyed after a mandatory six-month period.
"This is to ensure secrecy of the vote," the statement said.
Candidates who want to witness the incineration of the ballots at the Tuas South Incineration Plant on July 27 have to inform the Elections Department by noon on July 25.
The Punggol East was called following the resignation of People's Action Party MP and Speaker of Parliament Michael Palmer, who publicly admitted to an extramarital affair.
In the ensuing four-cornered fight, Ms Lee Li Lian of the Workers' Party won with 54.5 per cent of the votes.
She defeated Mr Koh Poh Koon of the PAP (43.7 per cent), Mr Kenneth Jeyaretnam of the Reform Party (1.2 per cent) and Mr Desmond Lim Bak Chuan of the Singapore Democratic Alliance (0.6 per cent).