The Transport Agency is coughing up another $5 million to keep workers on site at the massive Transmission Gully construction project over winter.
The billion-dollar motorway being built north of Wellington has had multiple delays and cost blowouts.
The agency said it was fronting the money so the six-week winter-work programme could be extended by a month until 7 August.
It already paid out $14m in May because of Covid-19, with the payments to form part of any final settlement.
It also shelled out $191m in February to cover delays from the Kaikōura earthquake and additional earthworks.
The agency said it was still negotiating with the public-private-partnership consortium building the motorway about the finish date and the final cost of the Covid-19 shutdown.
Transport Agency services general manager Brett Gliddon said extending the winter work programme while these negotiations continued would help minimise further delays.
"[The agency] must take a considered approach to making any decisions that involve taxpayer money and that is why an agreement on the new opening date and associated costs is taking time," Gliddon said.
He said the agency would not comment further until the talks were done.
Transport Minister Phil Twyford said the extension was a good sign because it showed talks were continuing.
He said the government wanted Transmission Gully completed as quickly as possible.
The motorway was initially slated for completion in November of this year but will not open now until well into 2021.