ACT Party leader Rodney Hide claims that state science company Niwa has deliberately misguided cabinet ministers over New Zealand's official temperature measurements showing global warming in New Zealand.

However, Niwa openly denied the allegation, revealed Michelle Hollis, communications manager of National Institute of Water and Atmospheric Research (Niwa).

"Niwa stands by the professionalism and integrity of its scientists," the organisation's chief climate scientist David Wratt quoted.

The clear line of evidences which added support to the claim included ship-based measurements and shrinking glaciers and land-based temperature measurements, such as those in Niwa's longterm 7-station series (of adjusted data) and an 11-station series.

Initially, Niwa told that the temperatures recorded from the seven locations -- Auckland, Masterton, Wellington, Hokitika, Nelson, Lincoln and Dunedin - depict clear temperature variations between years and also on long-term trends.

The 7-station series registered a temperature rise of 1.1degC per century, and the 11-station temperature record marked a rise of 1.3degC per century.

Niwa has earlier explained that its analysis related to measured temperatures involved internationally accepted adjustments for movement of measurement sites.