Waka Kotahi National Manager of Infrastructure Delivery Andrew Thackwray said since the Level 4 lockdown last year, NZTA and Fletcher Construction have been engaged in negotiations regarding a new opening date.
Thackwray said through those negotiations, Waka Kotahi now expected the expressway to open to traffic in late 2022.
"As we get closer to completion, we will have more certainty about a specific opening date and how the new road will change people's journeys throughout the region."
The project is currently almost three-quarters complete.
Its cost has increased from $330 million to a now estimated $405 million.
The motorway is designed to offer increased travel time reliability for people and freight, and reduce congestion at major pinch points such as Ōtaki.
PP2Ō will connect with the 18km Mackays to Peka Peka Expressway and the 1.25-billion-dollar Transmission Gully Motorway which is set to open in September.