Independent candidates Ooi Boon Ewe and Zeng Guoyan will not be contesting the Punggol East by-election.

Both candidates have left the Nomination Centre.

Candidates have to file their papers at North Vista Secondary School, the by-election's nomination centre, from 11am to 12pm on Wednesday.

Mr Ooi was seen outside the centre earlier this morning looking for assentors, while Zeng Guoyan turned up in riding a motorcycle around the centre.

When asked if he was contesting the polls, Mr Zeng said: "What's there to contest?" and walked off.