Saturday, November 8 is shaping as the most likely date for the election, allowing the Government to get the biggest possible electoral bang from its tax-cutting bucks and falling interest rates.
That suggests an announcement from Prime Minister Helen Clark could still be months away, according to parliamentary sources.
Australian betting agency Centrebet has installed November 8 as the favourite at $2.90 ahead of November 1, quoted at $3.70.
The last possible date is November 15 ($5.50 with Centrebet), but that is considered unlikely because it could smack of desperation and a desire to hang on to power as long as possible.
Miss Clark has indicated running "full term", but November 15 would leave little time to form a government and call Parliament together before Christmas.
Other possible dates have their drawbacks.
On November 1 the All Blacks play a test match against Australia in Hong Kong, kicking off at 9.30pm (NZ time). October 25 ($7 on Centrebet) falls on Labour Day weekend when many voters are out of their electorates and party volunteers are in short supply.
The Government has strong political motives for picking November 8. It wants voters to feel the full impact of the October 1 tax cuts flowing into pay packets as well as the extra cash from mortgage rate cuts.
Reserve Bank governor Alan Bollard is tipped to cut the official cash rate no later than September 11 or even at his next review on July 24. Once he starts cutting, he is expected to continue easing monetary policy, and there is another official cash rate announcement set down for October 23.
History suggests prime ministers give six to eight weeks' notice of election day, so an announcement is likely in mid-September.
In 2005 Miss Clark announced the election on July 25, almost eight weeks ahead of the September 17 polling day
In 2002 she gave just six weeks notice, but that was for a snap election on July 27 after the split in the Alliance.
If the election is to be on November 8, the best guide to an announcement would be 1993, when the November 6 election was announced on September 14.
Centrebet said more than 150 bets had so far been placed on the possible date.
National leader John Key is a firm favourite to win. He is paying $1.30 against $3.35 for Miss Clark, who is "struggling to attract a large bet", the agency said.
- © Fairfax NZ News
Has the sale of assets been successful?Related story: Govt lowers asset sales estimate
What do the stars have in store for you today?
Test your mind with our puzzles
The Little Things, Dilbert, Tom Scott and others
Dig into New Zealand's archives
Decide what news you want to receive when it suits you
Keep up with the latest news by making us your homepage