Google has banned political ads in Singapore ahead of elections, an opposition party said Wednesday, sparking accusations the tech giant was "kowtowing" to the tightly-controlled city's government.

The ban was imposed under controversial new rules aimed at fighting disinformation in the city-state, which critics fear could be used to stifle dissent.

General elections are widely expected within months and weak opposition parties are relying on social media to reach voters in a country where the mainstream media typically backs the long-ruling government.

But the Singapore Democratic Party (SDP), a key opposition group, said that Google had refused their request to buy ads on the site. Google had cited the new regulations, which prohibit adverts seeking to influence public opinion, according to correspondence between the US firm and the party posted on the SDP website by chairman Paul Tambyah.