The deadline to finish the massive Transmission Gully motorway project has been revealed.
The new 27km arterial route into Wellington was initially slated for completion in April but was pushed back by a month because of the Kaikōura earthquake.
It now says the project must be done by 1 November or the builder could be fined $16,000 a day.
It could be hit with a further $10 million charge if it is not done by 18 December.
The project is the first public private partnership in New Zealand for a state highway, which means it is being financed, designed, constructed and maintained by the private sector on behalf of the public sector.
Earlier this month the Transport Agency's former chief executive Mark Ratcliffe said after the motorway opened there would be still be further work required including landscaping and testing of technology systems.
The project is $1.04 billion after the Transport Agency agreed to a $190.6m settlement with the builder to avoid legal action after a cost blow-out from the construction problems.
Ratcliffe said the financial settlement would ensure Transmission Gully was completed to a high standard.
"Construction has been impacted by the challenging conditions of the site. The project has required an increased earthworks programme, creating further complexity, disruption and cost to the project through the additional consent requirements.
"These issues, and the impact from several storm events and the Kaikōura earthquake, have meant [the builder] has incurred significant additional costs to construct the project."
The NZTA said the money had come from its National Land Transport Fund and would not affect any other projects.