Vote 2017: Herald Election Forecast predicts winners in every electorate in New Zealand and shows movement in race between Labour and National

There's some significant movement in the latest update to the Herald Election Forecast, which shows Labour is on course to be the single largest party in Parliament.

Our model projects 54 seats for Labour, compared to National's 48. This is a change from the previous update, released on Tuesday, that forecast the big two parties would be deadlocked at around 51 seats each.

Today's update incorporates the latest poll, the One News Colmar Brunton poll released last night. That saw Labour widen their lead over National to 4 percentage points.

Our model crunches data from every major poll conducted in the past year and the results of every election since 1999. Check out the latest update in full, and find out how it was built here.

The path for either Labour or National to form a government is still likely to involve an alliance with New Zealand First. Wisnton Peters' party is projected to win 12 seats - making them a consistent factor in an uncertain race.

The Greens remain uncertain to cross the 5 per cent party vote threshold. Their lower and upper estimates for national party vote are 4 per cent and 5.4 per cent.

Today's update to the forecast now includes predictions for candidates by every electorate. These are based on previous election results and take into account any electorate-specific polling that has taken place.

The visualisation now also includes Maori electorate predictions, for candidate and party vote.

The new additions are perhaps the hardest part of election prediction due to tactical voting and lack of consistent polling at electorate level.

The forecast will be updated as soon as new polls become available. It'll be more responsive to the polls closer to the election on September 23.