But the club also insists its fight is for the wider community, as its neighbour, the Ravensdown fertiliser company, eyes the spaces next to it.
The Otago Daily Times reported in April the company, which owned Moller Park, was putting the squeeze on the Harbour club to stop using the ground, citing health and safety concerns.
Large trucks needed to negotiate a narrow road running around the edge of the ground to reach the Ravensdown plant, next to the rugby ground used by young children on Saturdays.
Harbour chairman Lance Spence has dismissed those concerns - arguing trucks did not use the area on Saturday mornings - and refused to budge.
Junior rugby games have continued to be staged there, and Mr Spence, speaking this week, said there had been no further discussions.
"They're not even emailing us. No-one is responding now."
The Dunedin City Council had delayed earlier plans to cease maintaining the ground and was continuing to mow the grass but only until the end of the year, he said.
Mr Spence continued to believe a development plan by Ravensdown was behind the sudden pressure to leave.
Moller Park had been used for rugby for 134 years, first by the Ravensbourne rugby club and later - following amalgamation with the Port Chalmers club in 1992 - by Harbour.
Access had continued based on a handshake deal, but after years of good relations Ravensdown wanted Harbour to sign a one-year lease, he said.
Mr Spence believed the lease would be used to remove the club, freeing up Moller Park and the now-vacant industrial site next to it for development.
"I believe there's been a plan from Ravensdown for a long period of time, and that's coming to a head, and they're frustrated we won't sign a year lease so they can kick us out.
"If they've got no intention to kick us off, and we've been there for 134 years, why are they wanting us to sign a year lease?"
Ravensdown works manager Tony Gray would not answer ODT questions this week, referring them to a company spokesman who also declined to comment in detail.
The spokesman would only say the company's position "has not changed", while insisting a development plan was not on the cards.
"There are no current plans to alter the land use, but things change and we have to have the capability to be flexible into the future."
Mr Gray had also earlier told RNZ the company had no specific development plans, but "things are changing" and it was possible in a year or two Moller Park might not exist.
Mr Spence said without Moller Park, the club would struggle to survive.
The vast majority of Harbour players came from the city, making Moller Park an important training base, and there was not enough space at Watson Park in Port Chalmers to accommodate all club teams, he said.
Moller Park was also the only community greenspace in the area, and was used regularly by the Ravensbourne Primary School and Ravensbourne Volunteer Fire Brigade as well.
The club had turned to a private investigator to research how a community greenspace came to be zoned industrial and purchased by Ravensdown, and to a Wellington-based commercial lawyer, Peter Barrett, who was "looking at all legal options".
"We need to make a stand for Dunedin and the community, long-term.
"Rugby doesn't really come into it."
