All four party candidates who have declared their intention run in the Punggol East by-election have arrived at the Nomination Centre hall.

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

The candidates are: surgeon Koh Poh Koon for the People's Action Party (PAP), sales trainer Lee Li Lian for the Workers' Party (WP), Desmond Lim for the Singapore Democratic Alliance (SDA) and Kenneth Jeyaretnam for the Reform Party (RP).

Independent candidate Zeng Guoyan was also spotted inside the Nomination Centre hall, while Ooi Boon Ewe was seen outside the hall seeking assentors for his nomination.

This is Singapore's second by-election in a year. It takes place just eight months after the last was held in the single member constituency (SMC) of Hougang.

Punggol East SMC fell vacant after former Speaker of Parliament and MP for the ward Michael Palmer resigned on 12 December 2012 after confessing to an extramarital affair.

The Returning Officer, Mr Yam Ah Mee, is expected to declare the results of the nomination process by 1pm Wednesday.

There are some 32,000 voters in Punggol East SMC and Polling Day has been set for Jan 26.