Auckland's $4.4 billion City Rail Link passed another milestone today when dignitaries and construction workers attended a ceremony to mark work starting on a new underground station in the central city.

"What the hell are you doing to my town? Whenever I come into the city there is a great big hole," said Transport Minister Phil Twyford, who enjoyed flicking the switch on a huge ground cutting machine that will start work on the perimeter walls.

Twyford was joined by Mayor Phil Goff at the controls of the 90-tonne machine, built in India especially for the project, and named Sandrine in honour of a woman working for a CRL contractor.

Last month, the tunnel boring machine for the CRL was named after Māori leader Dame Whina Cooper in keeping with a tradition that boring machines cannot start work until it has been given a female name.

The boring machine, due to arrive in kitset sections from China in October, will bore two tunnels from the Mt Eden end of the project as far as Aotea station.

The first walls of Aotea station are being built outside the Auckland Council's head office at the busy Wellesley St/Albert St/Mayoral Drive intersection that was closed to traffic in March.

The intersection and a council car park behind council's Bledisloe House on Wellesley St has been turned into a large construction site that will remain that way until the CRL opens in 2024.

The station will be 15m deep and 300m long and be the busiest train station in New Zealand. It will be built below Albert St between Wellesley St and Victoria St.

The station walls and roof are being constructed first and dirt will then be removed to build the platforms and concourse. Working top-down will reduce the impact of construction at street level.

Aotea station will connect with tunnels to Britomart and another new station, Karangahape, and then link to a rebuilt Mt Eden station and Auckland's wide rail network.

Twyford said the CRL is a huge project providing much-needed stimulus to the economy and jobs, saying 1000 designers, engineers and construction workers are already on site. Another 500 jobs will be created over the next year, he said.

Goff said Aotea station will transform the city centre and include an innovative design telling the unique stories of Tamaki Makaurau.