Mr Mackay made those comments in a submission on the Otago Regional Council's draft 2016-17 annual plan this week.
He told an ORC hearing panel in Dunedin the Dunedin City Council had been considering a harbourside development project for some time, including a city-sea bridge connection.
But the DCC had been "unable to commit to such an expensive project''.
He and others had already made submissions to the DCC's annual plan, asking them to commit further to the project, especially by implementing the "key city-sea bridge connection''.
"I am here today to request that the ORC engage in the harbourside development project in full partnership with the DCC.''
Developing the Dunedin harbourside would "make the city more attractive to visitors and residents''.
And the move would "boost the tourist industry further'' by encouraging visitors to stay longer, which would benefit the city economy.
The development would also provide a "much needed open public/water-recreational space for city residents'', including the growing warehouse precinct.
He noted that the ORC had already invested in the area by funding "the appealing cross-wharf structure'' along the base of the Steamer Basin.
And the DCC had already included in its annual planning to construct a "harbourside cycleway'' as part of a Port Chalmers to Portobello loop.
He noted that the cycleway was already DCC funded, and said there was also a need for connections to and from a city-sea bridge, which was the "main expense'' in the early part of the redevelopment project.
Funding was also needed for other uses such as lighting, benches, and green spaces.
A city-sea bridge would make the harbourside "more accessible from the city''.
In an interview, Mr Mackay said he loved Dunedin and knew the harbourside development would eventually happen on a slow "drip, drip'' basis, including through the cycleway extension.
He highlighted the success of Wellington's harbourside development and the boon that had been for that city's amenity and the increased enjoyment of both residents and visitors in the area.
By bringing together commercial and other partners, including institutions such as the University of Otago, Ngai Tahu and the ORC, ratepayers might not need to pay much for a successful and positive development in Dunedin.
Good planning, including an ecofriendly approach and use of latest technology, could help transform the area, making it much more appealing for Dunedin residents to use, as well as catering for the extra cruise ship visitors and other tourists that were projected to visit Dunedin in the future.
A project that was greatly in the public interest was being delayed by excuses, when vision and leadership could allow Dunedin people to enjoy the much enhanced harbourside amenity that was already being enjoyed by many other New Zealanders.
"It needs someone to take it [the project] and drive it,'' he said.
● Hearing panel chairman Cr David Shepherd thanked Mr Mackay for his submission.
He also noted that the ORC-related institutions owned only part of the land in the area, and the ORC was yet to decide where its proposed new headquarters would be sited.
Council chairman Stephen Woodhead thanked Mr Mackay for his "passion'', and Cr Bryan Scott said the submission was particularly timely.
