National has extended its lead over Labour and Greens after rising slightly in the latest Roy Morgan Poll.
The National Party rose 2 points to 48 per cent while Labour fell 2.5 points to 27.5 per cent and Greens fell 0.5 points to 11.5 per cent.
The poll was taken between August 4 and 17, which meant it partly took into account the impact of Nicky Hager's Dirty Politics book, released on August 13.
The survey also showed potential "king-maker" New Zealand First increased its share of the vote by 1.5 points to 6.5 per cent, its highest result since September.
National's coalition partners remained mostly unchanged. The Maori Party polled 1 per cent and Act and United Future 0.5 per cent each.
