Trail charitable trust chairman Stephen Jeffery said the venture had already attracted the attention of three operators before the trust formally sought expressions of interest last week.
Others who wanted to be involved had until June 21 to record their interest.
Two sections of the $3.4 million, 34km walking and cycling trail from the Roxburgh dam to Alexandra were almost completed - a 10km stretch from Alexandra to Doctors Point and a 12km piece from Lake Roxburgh to Shingle Creek.
Those two sections were expected to open in spring and the water taxi service would cover 12km of the Clutha River and Lake Roxburgh to link them.
''Because of the interest it's generated already, we're confident there will be suitably qualified and experienced operators prepared to carry out the water taxi service,'' Mr Jeffery said.
''There's been no final details yet on pick-up times and at the end of the day, it'll be a commercial operation, so we expect operators may want to include other things in the package. We're keen to hear how they'll make it work and there's a whole raft of other possibilities for add-on services that might be included.''
The trust had to look closely at revenue-generating opportunities and the concession process for a water taxi service was one way of doing that, he said. Last week, the Queenstown Trails Trust announced it had bought the Motatapu race event to get revenue to develop trails in the Wakatipu area.
Mr Jeffery said he had just returned from the North Island after taking a closer look at a 48km mountain bike race held there. There was potential for a similar event to be carried out using the Roxburgh Gorge and Clutha Gold (Roxburgh to Lawrence) trails.
''It's been made clear to us that we need to look at revenue-generating possibilities. There's no point mucking around; everyone's told us to fund our own trail, so we need to generate an income,'' he said.
Although the trust hoped to open up part of the trail before winter, a range of factors meant that would not be possible.
''I'm happy with the progress we're making but disappointed in the delays, which are out of our control.''
The middle section of the trail, where the water taxi service would be used, covered three separate properties, two of which were in the tenure review process, he said.
''The trust is still optimistic of being able to complete the full length of the trail; we're not ruling that out, but it may be a longer-term option. The fact of the matter is, we have to play with the hand that we've been dealt.''
