The funding is conditional on assurances of a $15m contribution from the Government or other sources by March 2.
The council's decision means construction could start at the Awatea St site in June.
Earlier, a last-ditch vote to halt ORC funding was lost 7-4 -- giving a clear indication the council would commit the $37.5 million towards the controversial project.

Early in the meeting Cr Michael Deaker put a motion that the council withdraw from funding the project.
However, that was lost by a margin of 7-4. Joining Cr Deaker in voting against funding the project were Cr David Shepherd, Cr Bryan Scott, and Cr Gerry Eckhoff.
The ORC meeting follows Monday's Dunedin City Council decision to support the stadium.