A 20.4m by 3.6m mural was found behind hardboard walls last week during demolition of the hall, an "amazing" find which Mr Entwisle said was created in 1892.
The mural featured in an October edition of the Otago Daily Times that year and was created as part of a Japanese-themed festival held in the hall.
The primary artist involved was David Ogilvie Robertson, who lived in Port Chalmers, but also in Japan for several years.
"Partly from his memory ... he produced this evocation of old Japan," he said.
The mural, which originally covered four walls, featured Mt Fuji, trading junks, a Shinto temple, feudal castle and pagoda.
The 1892 article said "it is doubtful if anything of the kind has been presented to a New Zealand audience before".
![Peter Entwisle Peter Entwisle](https://www.odt.co.nz/sites/default/files/styles/odt_square_small/public/files/user13493/ENTWISLE_peter_hs_240800.jpg?itok=QSS_VHxL)
The hall would have originally been built with just the cladding on the outside. More money would have been required to line it and, rather than allow it to resemble the interior of a pub, the community would have opted to decorate it with murals, he said.
He understands an earlier mural of an "icy region", such as Greenland or Alaska, also lined the hall, as mentioned in an ODT article in August 1889, and these would have been regarded in the same way a stage set would be today.
The mural would have been covered since at least 1901 and, while it was "ephemeral", there were "hardly any left now", he said.
The piece "ought to be preserved" despite the "considerable challenges" that would entail.
The fabric was "old and brittle", it was stuck to the wall with a multitude of small tacks and the paint was "kind of water-based opaque".
Also, the Dunedin City Council would have to foot the bill for the "quite massive costs of conservation", he said.
Architectural conservator Guy Williams said more details had emerged now the mural had been cleaned, but he was not entirely convinced of the history of murals in the hall.
"It is looking seriously interesting [but] the story is one that evolves; it can change.
"For us, there are still questions. It's not wise to jump to conclusions about what we've got," he said.
A community open day would be organised once "there was a comprehensive story to tell about what we've discovered".
Mr Williams, representatives from the Historic Places Trust, the Dunedin City Council, the Dunedin Public Art Gallery and the Otago Settlers Museum will meet next week to discuss the future of the mural as work begins on digging underneath the hall.
Demolition of the hall, which started last month, was flagged when the council decided four community halls were too many for it to own in Port Chalmers.
It chose to upgrade the Port Chalmers Town Hall, and the Pioneer Hall was transferred to a community trust. The Merchant and Navy Hall was sold and Garrison Hall, which sits on reserve land, was to be architecturally documented before being bulldozed, with the land passing to the Department of Conservation.
A 20.4m by 3.6m mural was found behind hardboard walls last week during demolition of the hall, an "amazing" find which Mr Entwisle said was created in 1892.
The mural featured in an October edition of the Otago Daily Times that year and was created as part of a Japanese-themed festival held in the hall.
The primary artist involved was David Ogilvie Robertson, who lived in Port Chalmers, but also in Japan for several years.
"Partly from his memory ... he produced this evocation of old Japan," he said.
The mural, which originally covered four walls, featured Mt Fuji, trading junks, a Shinto temple, feudal castle and pagoda.
The 1892 article said "it is doubtful if anything of the kind has been presented to a New Zealand audience before".
"It's amazing. I think it's wonderful - I've never seen anything quite like it before," Mr Entwisle said.
The hall would have originally been built with just the cladding on the outside. More money would have been required to line it and, rather than allow it to resemble the interior of a pub, the community would have opted to decorate it with murals, he said.
He understands an earlier mural of an "icy region", such as Greenland or Alaska, also lined the hall, as mentioned in an ODT article in August 1889, and these would have been regarded in the same way a stage set would be today.
The mural would have been covered since at least 1901 and, while it was "ephemeral", there were "hardly any left now", he said.
The piece "ought to be preserved" despite the "considerable challenges" that would entail.
The fabric was "old and brittle", it was stuck to the wall with a multitude of small tacks and the paint was "kind of water-based opaque".
Also, the Dunedin City Council would have to foot the bill for the "quite massive costs of conservation", he said.
Architectural conservator Guy Williams said more details had emerged now the mural had been cleaned, but he was not entirely convinced of the history of murals in the hall.
"It is looking seriously interesting [but] the story is one that evolves; it can change.
"For us, there are still questions. It's not wise to jump to conclusions about what we've got," he said.
A community open day would be organised once "there was a comprehensive story to tell about what we've discovered".
Mr Williams, representatives from the Historic Places Trust, the Dunedin City Council, the Dunedin Public Art Gallery and the Otago Settlers Museum will meet next week to discuss the future of the mural as work begins on digging underneath the hall.
Demolition of the hall, which started last month, was flagged when the council decided four community halls were too many for it to own in Port Chalmers.
It chose to upgrade the Port Chalmers Town Hall, and the Pioneer Hall was transferred to a community trust. The Merchant and Navy Hall was sold and Garrison Hall, which sits on reserve land, was to be architecturally documented before being bulldozed, with the land passing to the Department of Conservation.