Controversial right-wing blog Whale Oil claims it has been shut down by cyber attack and editor Cameron Slater says he has received death threats.
Mr Slater said has spoken to police by phone and plans to make a formal complaint on Wednesday.
Whale Oil controversially broke details of Auckland mayor Len Brown's two-year extra-marital affair with Bevan Chuang and has also been writing critical material about internet entrepreneur Kim Dotcom.
However, Cameron Slater said he is not accusing either of taking this action.
Mr Slater said he was able to ward off an initial attack on the blog on Monday night, but another attempt on Tuesday morning was successful.
He said whoever took this action did so using a so-called denial of service attack in which a vast number of messages causes a website to seize up.
Mr Slater said this sort of thing is expensive and can only be done by someone with a lot of resources. He is vowing not to be silenced.