The lawyer for the National Institute of Water and Atmospheric Research (Niwa) says court is not the place to test whether its temperature data is invalid.
Justin Smith also submitted to the High Court at Auckland that "expert'' witnesses called by the New Zealand Climate Science Education Trust, a branch of the NZ Climate Science Coalition, were not qualified to give evidence on climate science.
The trust has brought a case against the country's state-owned weather and atmospheric research body.
It says Niwa records, which show a national warming trend of almost 1 degree Celsius in the last century, are invalid and almost 50 per cent above the global average for the period.
The dispute relates to readings from the "Seven-station Series'' (7SS) - stations in Auckland, Masterton, Wellington, Nelson, Hokitika, Lincoln and Dunedin - used by Niwa for national temperature records.
Mr Smith opened the defence case before Justice Geoffrey Venning today.
"The defendant disputes the plaintiff's contention that it is not asking the court to rule on science but notes counsel's assurance that the plaintiff does not - and would not - ask the court to do so. But, in reality that is exactly what is asked of the court,'' he said.
"Niwa submits that the plaintiff's application of climate science methodologies lacks scientific credibility.
"However, Niwa, unlike the plaintiff, submits that the court is not the appropriate forum to resolve such scientific disputes.''
Mr Smith said there was a well-known judicial reluctance to resolve scientific debate, which "affects the plaintiff's case in almost every aspect''.
The NZ Climate Science Coalition is made up of people who question global warming and share concerns about "misleading information on climate change'', according to its website.
The trust said unscientific methods were used to reach Niwa's results, creating an unrealistic indication of climate warming.
"We're not saying climate change doesn't exist. We're saying let's at least make sure that evidence of this for New Zealanders is accurate,'' trust lawyer Terry Sissons told the court earlier this week.
Mr Smith today questioned the credibility of the evidence of two of the trust's "expert'' witnesses, including IT professional Manfred Dedekind, who said he also had qualifications and experience with statistical analysis.
"It is submitted that Mr Dedekind is not an expert on the application of statistical techniques in climate science and therefore cannot give evidence on the application of statistical techniques in climate science,'' Mr Smith said.
The same criticisms could be applied to retired journalist Terry Dunleavy, who also claimed to have wide ranging experience in public policy areas.
"He does not depose to having any qualifications or training in climate science and does not disclose any significant experience in this field.
"He appears to have either merely read other persons' work and correspondence and then either endorsed these views or presented them as his own.''
The hearing continues.
- APNZBy Matthew Theunissen Email Matthew