Police are hunting for two motorcyclists who sped away from officers at more than 300km/h.

The pair were seen travelling at excessive speeds near Upper Hutt over Queen's Birthday weekend.

At about midday on Saturday, two Japanese 1000cc sports bikes were spotted by police travelling on State Highway 2, just south of the Remutaka Range, at 247km/h.

"When the riders saw police, they accelerated away at speeds thought to be in excess of 300km/h," Wellington Road Policing Senior Sergeant Thomas McIntyre said.

"The speeds these riders have reached on a state highway are beyond dangerous.

"The risk they posed to themselves and other road users is unimaginable."

At 247km/h, the riders would have been travelling at just under 70 metres per second — had they crashed they would have killed themselves and possibly other road users, McIntyre said.

"Our roads are not a race track. This behaviour is unacceptable and puts others at risk."

Anyone with information about this incident or the riders involved is urged to contact their local station or call Crimestoppers anonymously on 0800 55 111.