The 25m tunnel under Waterfront Rd would accommodate the one or two dozen birds, on average, that used the North Otago Yacht and Power Boat Club boat ramp to come ashore at night, Oamaru Blue Penguin Colony marine biologist Dr Philippa Agnew said.
The penguins were ''very habitual'' and not easily dissuaded from using established nesting sites despite the high level of disturbance at the crossing.
Dr Agnew was confident the birds would use the crossing, as the neighbouring colony's birds had learnt to walk through a hole in a fence where a micro-chip reader was installed to read the ''grain of rice''-sized implants some of the birds wore in the back of their necks.
Network Waitaki, SouthRoads and Hynds each donated time or materials to the Waitaki District Council and Tourism Waitaki project.