The well-known political agitator, who ran for the mayoralty in Auckland three years ago, is standing for the Keep Our Assets group.
He will go up against incumbent Dalziel, a former Labour MP who succeeded Bob Parker as mayor in 2013.
Keep Our Assets is a Christchurch-based coalition of community groups, political parties and individuals campaigning against the sale of state and local assets.
The group has been demanding an end to secret Christchurch City Council meetings, and has asked for the renegotiation of the council's cost-sharing agreement with the Government to be delayed.
Minto would not comment ahead of an official announcement, which is due tomorrow morning.
Speaking from Singapore, Dalziel said: "I welcome the announcement. It will be good to able to debate these issues with John."
The issues Dalziel refers to are likely to largely focus on public asset sales.
In April this year, Dalziel said she was torn about whether she should run for re-election, but weeks later confirmed she would run again after being asked by an elderly resident at an Anzac service.
Minto, who writes for the Daily Blog and teaches science at Hornby High School, is most well known for his activism in the 1981 Springbok Tour. He moved to Christchurch early last year.
University of Otago politics lecturer Bryce Edwards said Dalziel would be safe.
"I don't think he has a chance. She's a shoo-in," he said.
However, Minto would have a "strong impact" on the mayoral debate, which would likely centre on the Christchurch rebuild.
"He'll be critical of it, particularly of Christchurch City Council and the sale of public assets," Edwards said.
"With John Minto it's always about grass roots activism, and to get a movement going rather than just winning the vote.
"However we do live in quite interesting, quite radical times. In other parts of the world we have seen older left-wing radical politicians doing well."
Edwards said there had been an "anti-establishment resurgence" that had seen plain-speaking politicians like British Labour leader Jeremy Corbyn and US Democratic leadership contender Bernie Sanders rise in prominence.
"He [Minto] could surprise us in the same way Corbyn and Sanders surprised their own countries."
- By James Pasley/Additional reporting: Christchurch Star
