"I will make clear my view that there are no circumstances in which the Auckland Council Governing Body would ever agree to sell the port land or enter into a lease agreement that would lock it into used-car and container port operations for decades - and that it is well known I am utterly opposed as Mayor," Brown's email said.
"You will all know that my mandate from Aucklanders is to retain the port land in public ownership and perpetuity and return it to mixed use for the people of Auckland as soon as practical, while maintaining cruise ship and coastal shipping services in the city.
"This will take time and there will need to be a just transition for every port worker that might be affected, but we need to get on with it."
Brown said he'd had constructive discussions on the future of the port land with "many of you", and politicians including Prime Minister Jacinda Ardern, and "look forward to working as a team to progress matters in the coming months".
"My media statement will go out at about 8.30am and will be available as usual on my Our Auckland page. I would appreciate your support for my stance on this matter."
Brown was voted in as mayor this month with an overwhelming majority. His mayoral style so far has been to issue media statements on his views and meetings with stakeholders and decline interviews where he can be questioned.
While he repeatedly states he has an election mandate to reform, council watchers say Brown needs to be inclusive and take councillors with him on that change journey or he will fail.
Meanwhile, in response to Herald inquiries of the council on a report by this publication it had been approached by Dubai-based port operator DP World and its investment partner, council general manager procurement Jazz Singh said there were no plans for council officers to meet those entities.
"The council is familiar with DP World, as a large operator of ports worldwide.
"While we are unable to go into much further detail on this matter, it is important to say that we are frequently approached by entities inquiring about acquisition of assets or taking an interest in assets we own.
"This includes recent interest in, and speculation on, the council's shareholder relationship with the Ports of Auckland.
"On these occasions we follow due process which typically comes with obligations of confidentiality, which we must honour.
"Any unsolicited bids we receive are evaluated by council staff first. Proposals that are not progressed do not get shared further ... If any approach is deemed significant it is reported to the appropriate council committee however details are not shared, just an outline provided."