Dave Cull.

The Dunedin City Council has been challenged to ban a gathering of mining industry representatives from meeting in a council-owned venue.

The New Zealand Minerals Forum is scheduled to hold its annual three-day conference at the Dunedin Centre in May, beginning with a welcome by Mayor Dave Cull.

The programme features talks on mining investment opportunities in New Zealand, including the ''substantial undiscovered underground coal deposits'' on the West Coast, which could be a ''game-changer'' for the industry.

It also included talks on the coal user/climate change ''dilemma'', best-practice environmental management and new low-carbon technologies.

The gathering in a council-owned venue was opposed by Coal Action Network spokeswoman Rosemary Penwarden and Generation Zero Dunedin co-convener Adam Currie, speaking at yesterday's Dunedin City Council public forum.

Many of the forum's presentations were about coal or other industries with high carbon footprints, promoting a ''business as usual'' approach ''to eke out more profits at the expense of all our futures''.

Also, coming less than two weeks after school pupils rallied for action on climate change, the council needed to do more, they argued.

They challenged Mr Cull to cancel his welcoming address and for the council to block the use of a council-owned venue for the forum.

Cr Aaron Hawkins questioned DCC chief executive Sue Bidrose on how Dunedin's approach compared with councils further north.

In Palmerston North, the city council was considering a new venues policy amid protests over the staging of the New Zealand Defence Industry Association Weapons Expo in the city.

In Auckland, the council had stepped in last year to ban alt-right speakers Lauren Southern and Stefan Molyneux from its venues.

Dr Bidrose said the DCC would be seeking a legal opinion, but the issue was ''complex and fraught''.

It would consider what sort of constraints could be placed on a lawfully operating organisation, and whether a ban from council-owned venues would be a breach of the Bill of Rights.

Once those issues had been explored, more information would be presented to councillors but that would not happen in time for May's minerals forum in Dunedin, she said.

chris.morris@odt.co.nz