Kevin Smith died while out biking

Conservationists were yesterday mourning the sudden death of a "pint-sized" battler who was at the forefront of some of the fiercest conservation battles of recent times.

Kevin Smith, 51, was out biking with his daughter when he collapsed and died.

He was "phenomenally fit", said Forest and Bird conservation director Kevin Hackwell.

Mr Smith's career stretched back to 1976 when he became part of a new, more radical environmental movement that protested against the logging of native trees and advocated for New Zealand's threatened species.

He was a rebel who eventually became a parliamentary insider, an activist and campaigner who, with former president Gerry McSweeney, helped transform Forest and Bird from a group of staid, elderly birdwatchers to a highly politicised and effective lobby group.

Mr McSweeney yesterday recalled the pair's days campaigning against logging of West Coast native forests.

"The ordeal of those vicious South Westland public meetings made anything that came after tame by comparison," he said.

Mr Smith was raised in Owhango, near Raurimu, where his father was a sawmiller.

He completed a botany degree, and in the mid-1970s joined the Native Forest Action Council, at the forefront of the campaign to protect native forest.

Hired as conservation director for Forest and Bird in the mid-1980s, Mr Smith left in 2000 to become parliamentary adviser to then-Conservation Minister Sandra Lee.

He continued in the role when she was succeeded by Chris Carter.

Mr Smith is survived by his wife, Tania, and three children.