NZ batsman Ryder in coma after bar bust-up

New Zealand batsman Jesse Ryder is in an induced coma at a Christchurch hospital after suffering serious head injuries in an altercation outside a local bar, police said on Thursday.

New Zealand Police said Ryder, 28, had been rushed to Christchurch Hospital after suffering the injuries early on Thursday morning and remained there in a critical condition.

"It appears that Jesse has been the victim of a serious assault and suffered head injuries as a result," Detective Senior Sergeant Brian Archer told a nationally televised news conference.

"Jesse was taken to hospital where he remains in intensive care in a critical condition in an induced coma after suffering multiple injuries."

Local media reports said Ryder had suffered a fractured skull and a collapsed lung. Archer would not confirm if the injuries were life-threatening.

Ryder, who had been drinking at the bar with teammates from Wellington, had been involved in two incidents, the first outside a bar with three other people.

Two of the three then followed him across the road to a nearby fast food restaurant, where one of them apparently assaulted the cricketer, Archer said. It was unclear whether the assault had been provoked.

Police were examining closed-circuit video footage.

"At this stage we have not identified the people involved in the incident but are following positive lines of inquiry," he added.

Ryder, one of the most gifted batsmen in New Zealand, was in Christchurch playing for Wellington against Canterbury in the semi-final of the domestic one-day competition on Wednesday.

He had been in a self-imposed exile from international cricket after a series of alcohol-related incidents, however.

Despite having publicly sworn off alcohol, Ryder had begun drinking again in recent weeks, New Zealand Cricket Players' Association chief executive Heath Mills told reporters.

"We have been dealing with Jesse for 10 years and there have been numerous issues documented in that time," Mills said.

"Jesse has been fighting some demons over the last few years and he has struggled with them. It will be an ongoing struggle for him but we are doing all that we can to help him.

"It shouldn't be a surprise in the future if we have to deal with isolated issues."

In 2008, Ryder needed stitches in his hand after he punched a window in a Christchurch bar, an injury that kept him out of the game for several months.

Following the Napier incident, Ryder voluntarily stood down from international selection to address his issues with alcohol.

"There are some alcohol protocols around the (Wellington) team but my understanding was that those protocols were being met so from that point of view the organisation does not have any direct concerns," Wellington chief executive Peter Clinton said.

"Our primary focus is his welfare. We remain very concerned and hope that he will recover."

Archer said he did not think that alcohol was a "contributing factor" in the altercation on Thursday.

Ryder had been expected to travel to India for the Indian Premier League with the Delhi Daredevils on Friday.

He was not expected to return to international cricket until New Zealand's tour of England in May-June, following their 0-0 draw in the recently completed home series.