The club is back talking to Zingari-Richmond after an approach in 2016 failed. But this time Harbour is keeping its options open and is also talking with Alhambra-Union.
Harbour club chairman Martin Paris said Harbour was serious about combining with another club and started negotiations with both clubs after discussions with Pirates fell over earlier this year.
''We are looking at merging and having talks with those two clubs but there is nothing definite happening,'' Paris said.
''The talks have not got very far at all ... but we are going back to the clubs to talk with them and we'll see what we can put together.
''We don't want to let this linger because we're pretty keen to move forward.''
Harbour is performing well on the field and will play in Saturday's premier final after beating Taieri 30-20 in the semifinal. But the club is struggling for depth below the top grade. It has a premier colts team but its senior team pulled out of the competition, leaving the premier side with no back-up.
Harbour needs to address its dwindling player base to future-proof the club.
''It is incredibly tough [getting players]. I've been involved for over 40 years and this is the toughest year I've ever had.''
Harbour had its 25th jubilee last season. It was formed in 1992 when the Port Chalmers and Ravensbourne merged. Both those clubs were more than 100 years old, so there is much history at Harbour.
Some of that history got in the way last time the club investigated entering into a strategic alliance with Zingari-Richmond.
The clubs looked set to join forces in a deal which would have had them field combined teams in all grades below premier level. They also planned sharing the cost of a development officer.
But Harbour's committee was not convinced it was the right move and eventually pulled out.
''It is very hard for old heads to let that name go, or that crest or badge of the club that you belong to go when you are forming something new. I felt that even when we merged with Ravensbourne.''
Harbour approached Pirates earlier in the year about a possible merger. Pirates dropped out of the premier grade at the beginning of the 2017 season, so that partnership seemingly had potential.
But it is understood the clubs reached an impasse about sharing the costs of a development officer - thought to be about $25,000 each - and were not able to reach an agreement.
Harbour president Lance Spence feels there is only room for eight teams in Dunedin premier rugby due to a steady decline in player numbers.
''We just think the best thing for the Harbour club in the long term is to amalgamate with someone in town. And it will be the best for the game, too.
''I think club rugby is struggling and I don't see the depth.
''It is not good for rugby for any clubs to drop off but I just think to strengthen up club rugby, I think there should be eight teams and there shouldn't be a bye.
''You can't go up to 10 because it will just weaken it too much.''