National is promising a $330 million injection into Horowhenua and the Kapiti Coast transport projects, if the party regains power in September.
Party leader Judith Collins said the election promise would connect Ōtaki to the Wellington’s commuter train network, which currently reaches Waikanae.
"In time, we will look to electrify and double-track the line to Levin, expanding even further the pool of commuters able to use the service," she said.
Ms Collins also reiterated the party promise to speed up the construction of a four-lane expressway between Ōtaki and Levin, costing $817.
She said if the party was to form a Government it would start construction in their first term.