The Elections Department (ELD) has lodged a police report after they were alerted to a recent discovery of empty election ballot boxes.
In a statement on Saturday, it stressed however that there were no implications on the secrecy of the vote and electoral process.
The ELD did not specify where the boxes were found, but a report on a socio-political site on Friday showed photos of empty ballot boxes purportedly found in a school storeroom last week. They appeared to have been used in the 2011 Presidential Election, in the electoral division of Bishan-Toa Payoh.
Empty boxes are discarded after the elections, the ELD said. It added that these are supposed to have been collected by their contractor, along with other discarded items, from counting centres for general disposal.
"Discovery of used empty ballot boxes would mean that these were missed by the contractor at the point of collection for disposal," it said.
The ELD was alerted to the matter by a member of the public on Tuesday.
Detailing the ballot counting process, the ELD said boxes are inspected by election officials at the polling stations, before they are used for the casting of ballots.
They then remain under the charge of these officials until they are emptied at the counting centres.
After polls close, election officials at the polling stations seal the boxes containing the ballots which have been cast, and transport them under police escort to the counting centres.
There, the boxes are opened, and the ballots are poured out, sorted and counted. This is carried out in the presence of candidates or their counting agents. The empty boxes are put aside to be collected by the ELD contractor and disposed of.
After the election result has been announced by the Returning Officer, the ballot papers and other documents used in the election are placed into separate boxes and sealed. They are then conveyed by police escort and retained in safe custody for six months at the Supreme Court. After six months, they are destroyed, unless directed by order of the President.
The process is open to observation by all candidates and their agents, and this rigorous process ensures secrecy of the vote, the ELD said.
In a separate statement on Saturday, the police said investigations into the matter are ongoing, and the Attorney-General's Chambers will be addressed once this is completed.