National has maintained a high poll rating and could govern without partners on 49.7 per cent in the latest TV3 Reid Research poll.
National would have 64 seats in a 121-seat Parliament.
Labour has slipped by 2.2 points 27.3 per cent.
The combined left bloc of Labour, the Greens and Internet-Mana would be 53 seats, 15 fewer seats than the combined bloc of National and its current partners of Act, United and the Maori Party, 68 in total, assuming each of the partners keeps an electorate seat.
Internet Mana polled 1.8 per cent. Assuming Mana leader Hone Harawira keeps Te Tai Tokerau, he would bring in Internet leader Laila Harre.
New Zealand First is down by two points to 3.6 per cent and would not be returned to Parliament.
The Conservatives are up by 0.5 and polled 2.8 per cent but would not make it to Parliament at all unless it won an electorate seat.
But if leader Colin Craig were to win East Coast Bays under this poll scenario, the party would have three MPs.
Prime Minister John Key poll 46.7 per cent, up 3.6, as preferred Prime Minister while Labour leader David Cunliffe is on 9.6, down 0.2 points.
The results: National 49.7 per cent (down 0.6), Labour 27.3 (down 2.2); Greens 12.7 (up 2.5), New Zealand First 3.6 (down 2), Conservatives 2.8 (up 0.5), Internet Mana 1.8, Maori Party 1.5 (up 0.9), Act 0.4 (down 0.1), United Future 0, no change.