Labour MP Phil Goff says any attempt by Ports of Auckland to expand further into the Waitemata Harbour could lead to heads rolling at board level.
The Auckland mayoral frontrunner was responding to a survey by accounting software firm MYOB showing 54 per cent of small and medium businesses want the port to move to another location.
The survey of 326 businesses found 31 per cent preferred the port stay at its downtown location and 16 per cent did not know.
Not one more metre of the harbour should be infilled for commercial activity
Of the alternative locations, 16 per cent suggested amalgamating with the Port of Tauranga, 15 per cent said it should be moved to North Port, 15 per cent to the Manukau Harbour, 7 per cent of the Firth of Thames and 1 per cent said other.
"The location of the port is hugely important to small business owners in Auckland," said MYOB spokeswoman Ingrid Cronin-Knight.
Goff, who has said "not one more metre of the harbour should be infilled for commercial activity", said it would be "a very unwise board that ignored the clearly expressed view of the business community in Auckland and the wider population of Auckland".
If the ports company decides to dig its toes in, Goff said, "then I would be looking at, over time, changing the nature of the people on the board of the port".
Following the release of a port future study in July, the port company flagged fresh plans for a 40m extension beyond the tip of two concrete piers at the end of Bledisloe Wharf.
Goff said what was needed was a regional, and preferably a national, port strategy in conjunction with the Government to make a decision about the long-term future of the port.
In the meantime, he believed cars should be moved off the port in the next three to 10 years when bulk cargo reached capacity. A carparking building that could consolidate the port's location is not favoured by Goff.
He was uncertain about improving road access to the port via Grafton Gully, saying he would prefer improved rail for the 20-year period it would take to move the port.
Vic Crone, the leading centre-right mayoral candidate, is also in favour of a more detailed port study and moving the port's operations over time.
"We could move the cars straight away," said Crone, who wants to create some "truly wonderful on our prime waterfront space".
Goff's position on the sale of the port is the land should be owned permanently by the people of Auckland and the business should stay in council ownership until its long-term future is decided.
Goff has also promised to keep the council's 22 per cent shareholding in Auckland Airport in public ownership. Asked if that meant the shares could be sold to the Government's Super Fund, he said they would love to buy them "but my view is to retain strategic assets in council ownership".
The MYOB survey also found that 39 per cent of businesses believe the council should balance transport spending on roads and public transport, 31 per cent want most spending on public transport and 26 per cent want most spending on roads. Three per cent did not know.