The statement by the Infocomm Development Authority (IDA) came as Singapore's biggest publisher confirmed users were having difficulty accessing some of its online sites, although no group has claimed responsibility for the incidents.
A person claiming to be from Anonymous last Friday hacked a reporter's blog on the website of the pro-government Straits Times newspaper, and warned of further attacks as it demanded greater Internet freedom in the strictly governed city-state.
In a video clip posted on YouTube on Thursday, a masked person claiming to represent Anonymous also warned the Singapore government it faced cyber attacks from the group unless it scrapped new rules requiring annual licences for news websites.
"The Singapore government takes cyber security and threats to its ICT (information and communication technology) infrastructure very seriously," the IDA said in a statement.
"Government agencies have been on heightened vigilance and have enhanced the security of their IT (information technology) systems in response to the declared threats against the government's ICT infrastructure."
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