The latest Roy Morgan political survey shows the support for Labour and Greens has bumped up enough to give a Labour-Greens coalition the seats it would need to govern.
The Government has taken a major hit in the new poll, which shows National down 3.5 points to 40.5 per cent last month.
Support of Labour is up one point to 35.5 per cent and the Greens edged up slightly to 13.5 per cent.
The gap between the two major parties has tightened - the smallest since the 2008 election when Helen Clark's Labour Government lost the election and brought the current National Government, led by John Key.
Since Mr Key became leader of National in November 2006, the National vote has never dropped below 40.5 per cent and has not dipped below that mark since October 2006 when Don Brash was still leader of the party.
The Maori Party is on two per cent (down 0.5), Act is unchanged on 0.5 per cent and United Future is at 0.5 per cent support (down 0.5).
Pollsters asked respondents `If a New Zealand election were held today which party would receive your party vote?'
The survey was taken between April 1 and April 14.