UPDATE 5.56pm: State Highway 29 near Old Kaimai Road is now reopen under stop/go traffic management after a slip closed the road earlier today.

A Waka Kotahi spokesperson says to detour via State Highway 2, or expect "long delays" until the remainder of the slip is fully cleared.

Earlier 3.06pm: State Highway 29 near Old Kaimai Road is closed following a slip.

"Heavy equipment is en route to clear the slip," says a Waka Kotahi spokesperson.

"Detour via SH2 or expect long delays until cleared."

Earlier 1.14pm: A slip is causing delays on SH29, Lower Kaimai this afternoon.

A SunLive reader says he has been sitting "stationary" for between 45 to 60 minutes.

"Traffic isn't flowing on the opposite side of the road either."

According to Google Maps, traffic is moving slowly in the area.

Image: Google Maps.