Transport Minister Phil Twyford said he was very pleased to be able to deliver O2NL to Horowhenua.
"It is so important to Horowhenua.
"NZTA has evaluated the entire project and has done some redesign work. A shared pathway for cyclists and walkers will run alongside the new expressway and one of the lanes each way will be for priority traffic such as public transport, freight and cars with multiple passengers.
He acknowledged that the stretch of road between Ōtaki and Levin is the most dangerous piece of roading in the country with 49 deaths and serious crashes in five years.
"This road has been on the books a very long time, long before National came out in the last election and called it their road.
"We chose to rebalance the entire infrastructure programme, rather than like National spent 40 per cent of the infrastructure budget on a select few bits of motorway. The rebalancing has allowed O2NL to be brought forward."
He said the many visits from local business leaders, campaigners and mayors from around Whanganui-Manawatū to his office have played a role in the final decision.
"They all talked me through the importance of this roading project for the district and the wider community. And it is important for that to happen."
"The funding for this is now locked in and this will give certainty to the community. I know that safety is a big issue on the existing SH1 as well as journey times."