Singapore's controversial law against online misinformation was challenged in court for the first time on Thursday as concerns mount it is being used to stifle criticism ahead of elections.
The legislation gives authorities the power to order corrections placed next to posts they deem false.
Since the law came into force in October, several opposition figures and activists have been ordered to place a banner next to online posts stating that they contain false information.
The Singapore Democratic Party (SDP), one of a handful of small opposition groups in the city-state, lodged an appeal last week after it was ordered under the law to "correct" three online articles.
The posts, on Facebook and the party's website, said many Singaporeans had been displaced from white-collar jobs by foreigners -- claims the government said were "false and misleading".
The SDP is seeking with its challenge, which got under way behind closed doors at the High Court on Thursday, to get the government order overturned.
Before it began, a judge rejected the party's request to have the case heard in open court, said deputy attorney-general Hri Kumar Nair, who is representing the government.
SDP leader Chee Soon Juan, who had argued that the case is of public interest, said the ruling was "very disappointing". The small party currently has no seats in parliament.
The challenge was filed against Manpower Minister Josephine Teo, whose ministry last month requested the corrections and later rejected an application to withdraw its order.
While it is praised for its economic management, affluent Singapore's government is also regularly criticised for curbing civil liberties.
The People's Action Party (PAP) has ruled Singapore for decades and looks set to comfortably win polls expected within months, with a weak opposition seen as little threat.
The government insists the misinformation law is necessary to stop falsehoods from circulating online that could sow divisions in the multi-ethnic, multi-faith country.