Transport Minister Simeon Brown says an idea to build a "mega tunnel" under Wellington City from The Terrace to Kilbirnie could be a better option than a second Mt Victoria tunnel, but there needs to be further investigation.

The NZ Herald revealed this morning that the government had asked NZTA/Waka Kotahi to investigate the feasibility of the mega tunnel, but so far there are no rough costs.

Brown joined Wellington Mornings host Nick Mills to discuss the proposal. 

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