Dunedin historian Gordon Parsonson has been presented with a commemorative coin to acknowledge thousands of hours of voluntary work, transcribing handwritten journals by pioneer Anglican cleric the Rev Samuel Marsden.

The bicentenary of Marsden's first sermon in New Zealand, at Oihi Bay in the Bay of Islands, on December 25, 1814, is being celebrated this Christmas in the Bay of Islands.

Bishop Kelvin Wright presented Mr Parsonson with the coin, which also commemorates the bicentennial, at a small ceremony at the Hocken Library in Dunedin, last week.

Mr Parsonson, 94, has transcribed many thousands of pages of handwritten Marsden material, both journals and letters, as well as related mission archives.

The fruits of more than 20 years' work will be made available online by the Hocken for the first time next month.

Bishop Kelvin said that having greatly improved access to Marsden's journals and letters was of huge' benefit to the Anglican Church.

Marsden had played a ''foundational'' role in Christianity in New Zealand and had preached the first Christian gospel in New Zealand in his Christmas Day sermon 200 years ago.