A truck hit the rail bridge over Ngauranga gorge earlier this morning. (File Photo)

The Kāpiti Line train service has been given the green light this morning after a truck hit a rail overbridge just north of Wellington.

A truck carrying a digger hit the rail bridge over Ngauranga Gorge southbound lane off-ramp just before 5am on Friday.

The road is now clear, and train services will run as scheduled, Metlink said.

Train services on the line were briefly suspended and a 25kmh speed restriction was put in place between Takapu Rd and Wellington while KiwiRail staff visited the site.

The speed restriction has now been lifted.

The southbound lane on the Ngauranga off-ramp was briefly blocked due to the crash.