Support for the National Party has dropped below 50%, an opinion poll taken after the Budget shows.
The Television New Zealand poll was released on Monday and conducted in the week following the Budget on 24 May.
It showed that National was down four percentage points to 47%.
Labour has risen four points to 33%, while the Green Party was up 2 points at 13%.
New Zealand First slipped one point to 2%, while the Maori, ACT and Mana parties polled at 1%.
However, National's leader John Key remained the preferred Prime Minister on 48%, while Labour leader David Shearer was up three points at 14%.
Just over 1000 people were surveyed for the poll, which had a margin of error of plus or minus 3.1%.