Claims by a New Zealand scientist that Maori carry a gene linked to a range of anti-social behaviours have been labelled appalling by a leading New Zealand geneticist.

Dr Nicola Poa, research fellow at Christchurch School of Medicine, said it was unheard of to link a gene to race-based behaviour.

"It is pretty contentious to be tagging a gene, especially with that type of behaviour, to an ethnic race. There are huge ethical behaviours behind it. I was appalled.

"You have to be very careful. It is quite a big leap to be able to connect it to a type of behaviour. You really need input from psychologists or psychiatrists to do it at the molecular level. Genes are the basic building blocks. It's a big leap to adapt it to someone's behaviour."

Dr Rod Lea, a genetic epidemiologist at the Institute of Environmental Science and Research in Wellington, told an Australian genetics conference this week that the monoamine oxidase gene (MOA), carried by a large number of Maori, could be a key to addressing several health issues.

The gene, dubbed the warrior gene, has been associated with risk-taking, including gambling, addiction and aggression.

Dr Sam Hancox, of Otago University's Dunedin Multidisciplinary Unit, said genetics and their link to behaviour required recognition of environmental factors.

"It is extremely unlikely that a single gene explains anything. It is almost always a combination of factors, particularly environmental influences.

"There is no gene for making great rugby players, but then if you have the wrong person no amount of coaching is going to ensure he will be an All Black. You have to have the right set of genes and the right set of a coaching."

In 2002 the Otago-based unit researched the effects of a variation of the MOA gene on abused children.

The research found few of those producing high levels of the variant MAOA gene developed antisocial behaviours, despite being maltreated. However, around 85 per cent of those severely abused with low levels of MAOA developed antisocial behaviours.

Meanwhile, Dr Lea has moved to emphasise that the nature of his research is to assist in Maori health, especially high Maori smoking rates.

Speaking on National Radio yesterday, he said the focus of his research was to identify genes to determine why Maori smoking rates were among the world's highest. He said around 60 per cent of Maori carried the MOA gene, discovered by United States researchers, compared to 30 per cent of Caucasians.

"This gene has been linked to different anti-social and risk-taking behaviours, but the link has been usually quite weak, and often is only present in association with non-genetic factors - that is, other factors such as upbringing, socioeconomic circumstances, other lifestyle factors."

Meanwhile, Maori Party co-leader Tariana Turia said the warrior gene reports demonstrated unbalanced treatment of Maori by the media.