Mayor Len Brown, who left a debate on the zoning issue to attend the Cricket World Cup opening party in Christchurch, will not say if he supports the decision.
"Democracy is dead in Auckland," said Mr Sefton, who has more than 50 years' experience in yachting and Team New Zealand circles.
"This is the city's future and the harbour is the essence of the city. I think it is important enough that there should be a referendum," Mr Sefton said.
The boating fraternity, Mr Sefton said, was gathering its forces and would probably come out vehemently against what is proposed.
Both the Royal New Zealand Yacht Squadron, with 2600 members, and the Auckland Yacht and Boating Association, representing 49 boat clubs, are discussing a response to the latest moves by the council and ports.
Penny Whiting, who has been running a yachting school on the inner harbour for 49 years, said she was mortified at the narrowing of the harbour and big tidal flows between the port and Devonport.
So too was David Ingram, of Sailing Auckland, who said: "When you narrow the gap, the tide moves faster and since engines cannot be used when racing, in a strong spring tide many boats will be going backwards."
Barry Holton, of the Westhaven Marina Users Association, said members were deeply concerned about the consequences of the proposed wharf extension.
"Any further narrowing of the Waitemata Harbour may have adverse effects on the quality of the harbour environment and access to the Hauraki Gulf," he said.
The association, he said, wanted to consult with the council and ports company.
A ports spokesman said the company was happy to talk with the association and others.
"The proposed wharf extensions can't possibly have any effect on the tide, because they are piled structures. The water just flows through them.
"When we apply for resource consent for reclamation, we will commission reports on the impact on tidal flow and other environmental matters.
"At this stage there is simply no evidence for the claim that the reclamation we are proposing will make sailing more difficult," the spokesman said.
Boaties speak out
• Opposed to further reclamation of harbour for port use
• Opposed to council weakening rules for further reclamation
• Talking among themselves about what action to take
• Calls for a referendum by one yachting veteran
• Ports of Auckland happy to address boaties' concerns.