The 90 metre extension will increase the international baggage hall floor area by approximately 2,500sqm.
It will cost NZ$8.4 million and be completed by 30 November 2014.
Adrian Littlewood, Auckland Airport’s chief executive, says: “We are committed to delivering on our 30-year vision for the ‘airport of the future’ and the expansion of our international baggage hall is the first step of many towards a new combined domestic and international terminal.
“An additional, sixth, baggage belt is required in the international baggage hall before the 2014 summer peak travel season and will have sufficient capacity to handle the luggage from an A380 flight.
"We also expect a seventh baggage belt will be required shortly thereafter due to further passenger growth."
Auckland Airport announced its 30-year vision for the airport in March.
It includes building the combined domestic and international terminal, and building a second runway by around 2025 with a possible 890m extension in 30 to 50 years.
The airport estimates that the number of passengers using the airport every year will almost treble, from 14.5mppa in 2013 to 40mppa in 2044 and the number of flights almost double from 150,000 a year in 2013 to 260,000 in 2044.