Sir Neil, a former chairman of English Heritage, and an authority on industrial heritage, spoke to more than 60 people at a function at the museum this week.
"There are more pyramids in Egypt than there are gasworks in the world," he said.
Sir Neil has previously said that the Dunedin facility was one of the world's finest gasworks museums and added that it was also "part of Dunedin's history" and a significant educational resource.
The museum was maturing like a fine wine which was not quite ready but soon would be, he said in an interview.
Barry Clarke, the gasworks museum trust chairman, Ann Barsby, another leading figure in the trust, and many other supporters of the Dunedin City Council-owned gasworks, as well as several city councillors and Otago Settlers Museum director Linda Wigley were among those attending.
Sir Neil spoke after a brief illustrated talk had brought visitors up to date with recent developments.
He noted considerable progress was being made, with the city council and community donors providing significant support to safeguard and restore the museum's fitting shop, which was earlier threatened with collapse.
Work is continuing on the fitting shop, with the previously sagging brick walls being brought into line, and with the roof to be replaced.
Sir Neil said the museum needed more volunteers to help staff counters and act as guides.
He acknowledged there had been past frustrations and delays, but crucial support had been gained and better times lay ahead.
