Workers' Party candidate Lee Li Lian said on Thursday that the Punggol East by-election is also a barometer for how well her party has performed since the last general election.
WP chairman Sylvia Lim had said on Monday that the election would be a test of the Government's performance.
Asked by reporters ahead of a meet and greet session if her party was also under scrutiny, Ms Lee said yes.
The election will show if people have the confidence to vote for the WP, based on their track record, she added.
Ms Lee also said that in her conversations with residents on the campaign trail so far, she has received feedback about the lack of feeder bus services, childcare services and other amenities.
Ms Lee hopes to visit every household over the nine days of campaigning, starting with the ones she failed to cover at the last general election. During the 2011 campaign, she covered 60 per cent of households, she said.