The other project was a proposal to build an atrium linking two of its Forth St buildings - and upgrading them both - which was likely to cost more than $10 million, chief operating officer Philip Cullen said.
Both projects were in the planning stages and yet to be approved, he said.
Mr Cullen said the polytechnic was working with a partner which would pay for the new hall of residence, should it go ahead.
The plan was to build it on a site close to the polytechnic.
Details about the exact location and the business partner were confidential, he said.
The costs of the projects were being determined, but it would be more than $12 million, he said.
A range of factors supported the idea of building a hall of residence for students, including an increasing number of students coming to the polytechnic from outside Dunedin, including from overseas, and the fact demand for hall of residence places out-stripped supply, he said.
There was evidence some first-year students would not come to study at the polytechnic ''without safe and secure accommodation and pastoral care'', he said.
''Experiencing the first year of tertiary education in a hall of residence is one of the most valuable experiences enjoyed by students. This is particularly so for younger students, who need to gain confidence and a network of friends before they go flatting.''
The plan also fitted with the polytechnic's aim to diversify its revenue stream.
The second project included building an atrium linking the polytechnic's H and F blocks, upgrading both blocks and installing a concourse in front of H block.
The ground floors of the upgraded buildings and the new space would contain a cafe, have computer and Wi-Fi access and meeting rooms. The project would also include landscaping work and upgrading the fire safety of the two buildings.
Mr Cullen said there had been ''no significant building development'' on the Forth St site since the mid-1990s. Learning needs had ''significantly changed'' since then.
It was not known when either project was likely to go ahead.
Mr Cullen's comments came after the University of Otago this week confirmed it had purchased the 128-room LivingSpace hotel, which it plans to convert into student accommodation.
