Four motorcyclists have been killed in different crashes around the country; capping off a horrific start to the weekend on our roads.

Emergency services were called to three separate accidents involving motorcycles yesterday afternoon.

The first accident happened about 12.45pm in Southland; where two motorcyclists were killed in Isla Bank, northwest of Invercargill.

A third rider suffered critical injuries in the same crash - which involved three motorcycles. It is understood they were taking part in a fundraising ride.

Just over two hours later, about 3.20pm, emergency crews in Auckland were called to a crash on Henderson Valley Rd after reports that a motorcyclist had crashed into a ditch.

Police soon confirmed the rider died at the scene and a section of the road - between Candia Rd and Pine Ave - was closed off for some time as authorities worked at the scene.

Shortly after 4pm, another motorcyclist lost their life in a crash on the West Coast.

Fire crews, police and St John staff attended the scene on Lower Buller Gorge Rd.

The NZ Transport Agency for Canterbury and the West Coast later advised motorists that the section of State Highway 6 at Inangahua was closed until further notice as a result.

The four deaths came after two people were killed in different crashes in Christchurch on Friday.

A passenger of a car that collided with a motorcyclist at the intersection of Colombo and Sandyford Sts, in Sydenham, just after 11am, died at the scene.

The driver and the motorcyclist suffered serious injuries, police said.

Later that night, a teenage girl died when the car she was a passenger in smashed into a school building on Gloucester St.

Three others - including the male driver - suffered serious injuries and were taken to hospital.

The vehicle had minutes before been pursued by police.

Police yesterday said the pursuit had been abandoned shortly before the crash occurred.

The Christchurch crashes resulted in Canterbury Police releasing a statement urging people to buckle up and drive safely.

Superintendent Lane Todd said it was a simple message - seatbelts save lives.

"It's that simple. Anyone who chooses not to wear a seatbelt only increases their risk of injury or death if they end up in a crash.

"Being properly restrained reduces your chance of death or serious injury in a crash by 60 per cent in the front seat and 44 per cent in the back seat.''

TIMELINE:
• 12.45pm: Two motorcyclists killed in a crash in Southland. A third motorcyclist was last night in a critical condition.
• 3.20pm: Motorcyclist crashes into a ditch on Henderson Valley Rd, West Auckland.
• Just after 4pm: Motorcyclist crashes on Lower Buller Gorge Rd, West Coast.