There is evidence of the "widespread use of racist, aggressive and militarised rhetoric" against foreigners on social networks, said a press release issued by 12 independent groups including Maruah, Singapore's main human rights group.
It warned of a worrying trend "blaming foreigners for social ills" such as overcrowding, local unemployment, often posted anonymously online.
"We, the undersigned, are alarmed by the recent surge of racism and xenophobia in Singapore," the statement said.
It added the key to addressing frustrations felt by many Singaporeans was for the government to change the policies which caused marginalisation and inequality.
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Among the other signatories were organisations advocating women's and migrant workers' welfare, gay rights.
The statement came a day after a Philippine independence day celebration scheduled for June 8 in downtown Singapore was cancelled following a virulent campaign by online commentators.
Migrant workers from South Asia have also been attacked and ridiculed online following a riot last December triggered by the death of an Indian worker in a road accident.
Western expatriates seen to have behaved arrogantly have also been denounced by Singaporeans.
A survey by Singapore's government-linked Institute of Policy Studies released this year showed that over 30 per cent of citizens and permanent residents felt that nationality-based prejudice had risen over the past five years.
Singapore's citizen and permanent resident population of 3.84 million is 74 per cent ethnic Chinese, 13 per cent Malay and nine per cent Indian, with the rest made up of other immigrant groups.