Speedster assaulted officer

Punches rained down on an officer's head moments after he was struck by a teen's motorcycle helmet following a high-speed pursuit through north Dunedin.

Ayden Watt (19) appeared in the Dunedin District Court yesterday, pleading guilty to charges laid after the July 9 incident.

They included aggravated assault, driving while disqualified, driving in a dangerous manner, failing to stop and possessing cannabis for supply.

Prosecutor Sergeant Graeme Evans said in the summary of facts Watt was riding a Hyosung motorcycle in Gt King St when police signalled for him to stop near the intersection with Opoho Rd about 9.50pm.

The unemployed Dunedin man rode into the cycle lane and accelerated along North Rd, reaching speeds of 80kmh, passing motorists in the process.

Turning left into Northumberland St, he rode around the block before arriving back on North Rd.

He continued travelling southwards, reaching 100kmh - twice the legal speed limit there.

Watt turned into Duke St, travelling the wrong way, before turning right into Castle St North.

He rode through a stop sign at the Castle and Dundas Sts intersection at about 40kmh.

He lost control in Castle St, crashing close to a construction area near the University of Otago.

Watt fled on foot and was pursued by police.

When the officer caught up with him, he took off his helmet and swung it at the officer's head.

The officer was struck several times on his arm as he tried to shield himself.

Watt lost hold of his helmet but ''continued raining punches'' on the officer - striking him seven or eight times on the right side of his head.

Watt tried to trip the officer, causing him to stumble, then ran to the helmet and grabbed it again, swinging it in front of him when the officer approached.

Once detained, a search of Watt's backpack found it contained 69 small (1g) bags of cannabis as well as eight larger (3g-4g) bags.

It also contained a container of liquid with ''acid'', sold for $30 a drop, and four plastic pill caps (value undetermined).

Judge Belinda Pidwell remanded Watt in custody to reappear on September 26.