WELLINGTON (AFP) - New Zealand Prime Minister John Key has won a third term with a strong showing in Saturday's general election, according to projections by leading television networks.

Both TVNZ and TV3 gave Key's centre-right National Party around 48 per cent of the vote, meaning he can rule either in his own right or with support from existing coalition partners.

"That's 60 seats for National, they're in a very strong position and with the likes of (coalition partners) ACT and United Future they would be across the line," TVNZ political reporter Corin Dann said.