Two motorcyclists clocked at over 300 km/h have been branded "lunatics".
But police believe they're close to tracking them down after an appeal for the public to help identify them.
The riders were spotted by police on Saturday, travelling at 247km/h on State Highway Two just south of the Remutaka Ranges.
When the motorcyclists realised they'd been seen, they accelerated to over 300km/h.
In a statement, police said members of the public had been "very supportive" of the attempts to identify the riders, and that they had "strong lines of inquiry".
Upper Hutt mayor Wayne Guppy said the speeds the pair were driving at was "absolute lunacy".
"They're not only endangering themselves, more importantly they're putting innocent people at risk and endangering them," he said.
"Someone will know them, because when you get people doing what they've done, they can't help themselves talking about it.
"There will be someone who they're bragging to, or talking to, that will know about it.
"If you know them, then put your hand up and say 'that ain't acceptable in our community and I'm going to dob you in'."
Guppy said people in Upper Hutt weren't the type to put up with that type of behaviour.
"Look it's zero tolerance to it, and our community has had enough of it."
At about midday on Saturday June 2, 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 at the time.
"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 247kmh, 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 555 111.