Both of the main television polls show the National Party has increased its lead over Labour.
The One News Colmar Brunton poll and 3 News' Reid Research now show at least a 20-point gap between the two parties.
The One News poll has National up four points to 51 percent, compared with Labour down one to 30 percent.
The Greens are steady on 11 percent and New Zealand First is down two to 4.8 percent.
The 3 News poll also has National up four points, to 50 percent.
It shows Labour down one to 29 percent, alongside the Greens, also dropping one point to 10 percent.
Both polls have John Key at 43 percent for preferred Prime Minister, with Labour's David Cunliffe around 10 percent.
Both surveyed 1000 voters and have a margin of error of plus or minus 3.1 percent.