One person is dead after a serious two-vehicle crash that has closed State Highway 1 near Tīrau.

Emergency services are responding to the crash, involving a bus and a car, which was reported just after 2pm today.

A photo from the scene of the crash shows a bus on the side of the road, along with another damaged vehicle.

St John said 13 patients have been transported for treatment, with two of them critical and four serious. Several rescue helicopters have been scrambled to the scene.

A police spokesman said police were called to a two-vehicle crash near the intersection with Paparamu Rd just after 2pm. SH1 at Piarere is closed.

“Motorists are asked to take alternative routes where possible, or delay travel.”

One person commented on Facebook, “Oh no! I heard all the sirens and thought it may have been an accident”.

Another said, “Bus versus car. It’s not good.”

Another local resident posted: “I just seen 3 appliances leave Putaruru and 3 cops and Ambo race through from Tokoroa...It must be catastrophic.”

A Hato Hone St John spokesperson said seven ambulances, five helicopters and three rapid response units have been sent to the scene.

Patients were taken to Waikato, Rotorua, Tauranga and Auckland Hospitals by road and air.

Traffic backing up on SH1 near Tirau after a major crash involving a bus left 13 people injured. Photo / Maryana Garcia

The Waikato Westpac Rescue Helicopter confirmed it had transported a patient in critical condition to Waikato Hospital.

“The Greenlea Rescue Helicopter is still on scene,” a spokesperson said.

The Herald understands the Auckland Westpac Rescue Helicopter is also responding to the accident.

A detour is now in place after the serious crash closed a section of SH1 north-west of Tirau. Photo / Google

Waka Kotahi NZTA has also posted about the accident, warning motorists to expect delays.

“Due to a serious crash, State Highway 1 is closed between Tirau and Piarere Rbt due to a crash near Paparamu Rd.

“This section of SH1 is likely to remain closed for some time today as NZ Police undertake a serious crash investigation. Delay your journey or allow extra time for a detour via SH27 and SH29.”

Stop/go traffic management is in place around the accident site.

A photo at the scene shows the traffic backing up.

The Serious Crash Unit has been notified.

More to come.