WORKERS' Party (WP) leaders took the Government to task for the influx of foreigners since 2005, citing it as the root of many problems in Singapore.
The immigration policy has led to high housing prices, frequent MRT breakdowns and a lack of open spaces, they charged at a rally in Punggol East last night.
The country, they added, was losing its sense of identity.
WP chief Low Thia Khiang also restated the party's stand on population, in response to a comment by Deputy Prime Minister Teo Chee Hean that the WP had avoided doing so.
He said WP was not an anti-immigration party. It welcomed those who could contribute to Singapore, but immigration must ultimately benefit Singaporeans.
On foreign workers, Mr Low also said his party's stand was clear: Singapore should not be over-reliant on them, and should not allow them to take away the rice bowls of locals.
"This is not protectionism but the responsibility of the Government to the people," he said.
Accusing Mr Teo of "misleading" voters when he said WP had been evasive about its stand on foreign workers, Mr Low said that he had fleshed out the party's view in Parliament last March.
He had argued then that a reduction in foreign-worker quotas should be calibrated by industry, depending on which ones needed them more.
In that debate, Deputy Prime Minister Tharman Shanmugaratnam said such a tailoring was difficult to implement, and accused WP of flip-flopping, since the party had previously argued that foreign workers dampened the wages of Singaporeans.
Mr Low was joined by Aljunied GRC MP Pritam Singh last night, who put the spotlight on the lack of greenery and open spaces as the result of population growth.
He cited the example of Pasir Ris residents unsuccessfully petitioning that a forest due to be cleared for an international school be retained.
He also slammed the Government for allowing housing prices to skyrocket, dismissing the government line that its cause - increased foreigner numbers - could not be anticipated.
He added: "Unlike other immigrant-friendly countries that have a countryside where citizens can retire to and relax in, this little red dot is all we have."
Punggol East candidate Lee Li Lian criticised the Government for its "short-sightedness": not planning infrastructure ahead of the influx, resulting in overused MRT services and its breakdowns.
Finally, WP chairman Sylvia Lim lamented the loss of a sense of home because of population changes: "Sometimes when I am crossing at traffic lights, I close my eyes and listen to people talking around me and can imagine myself living in a different country."