Auckland's domestic airport is facing their biggest redevelopment since the terminal opened 57 years ago.

Plans have been signed off to merge the domestic and international terminals and have them sit under one roof.

The new airport will include 12 new domestic gates and a shorter - and covered - walk between terminals.

Auckland Airport’s chief executive Carrie Hurihanganui says the existing terminal isn't fit for future purpose.

"We are focused on ensuring that we do have a resilient terminal going forward that's going to last 30 to 40 plus years." 

The new combined terminal is set to open between 2028 and 2029.

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