The Auckland stadium shuffle comes with another warning - music fans will face bigger ticket prices to see big acts in the city.
Mt Smart Stadium - which has hosted giant gigs by the Rolling Stones and the Eagles in recent months - will have its 47,000 capacity slashed by 10,000 seats when the venue is transformed into the new home of speedway.
Veteran music promoter Phil Sprey from Capital C Concerts has staged stadium shows in New Zealand for Bon Jovi and Elton John. He said if concerts did remain at a new-look Mt Smart, premium tickets for superstar acts that played at the venue costing $500 could rise to $750 or more, $200 tickets could become $300, and so on.
"The artists and promoters will want the same returns and the only way that could happen on a reduced capacity would be to increase ticket prices to the level where they could cost crazy money."
The Herald on Sunday understands that issues getting consents for night-time events at Western Springs meant it was unlikely to host some gigs Mt Smart could no longer put on. Independent promoter Ian Magan is staging a gig by rock giants AC/DC for 55,000 fans at Western Springs in December. He said a reduced capacity at Mt Smart would significantly affect its viability as a music venue.
"I would rather put a concert on at a bigger place than raise ticket prices, which are already at very high levels."
Vector Arena boss Stuart Clumpas believed speedway at Mt Smart was "not the right move".
"I am a motor racing fan and it makes staging gigs miles more difficult. The whole policy needs a bit of a rethink and I think public opinion falls that way, too."
Speedway promoter Bill Buckley, who will see his operation transfer from Western Springs to Mt Smart, believed the upgrade meant the Penrose ground would not be suitable for major live acts.
Eden Park Neighbours' Association president Mark Donnelly said the organisation would be "very strongly" opposed to concerts being held at the central city stadium.