The busy Mt Eden Train Station will be closed for about four years to allow for work on Auckland's City Rail Link.

Photo: Supplied / CRL

Today's announcement comes as construction crews prepare to ramp up work on the country's largest infrastructure project from the start of 2020, with Aucklanders told to expect significant disruption over the next few years.

City Rail Link chief executive Sean Sweeney said 2020 would see the beginning of the largest phase of the CRL project - linking Wyndham St in the central city to Mt Eden.

"Mt Eden will be the major site where the tunnel boring machine will be assembled and launched. It'll do two drives for the two tunnels - they'll both come from Mt Eden.

"There will be interruption along the way but rest assured we've spent a lot of time try to extract the lessons from what's gone wrong and what hasn't gone wrong on lower Albert Street."

The station will be closed from June next year to 2024, allowing for underground tunnelling and a complete upgrade of the station itself.

Roughly 250 people an hour get out at Mt Eden Station during peak hours, who will have to either travel to the Kingsland or Grafton train stations or to take buses into the CBD.

A dedicated bus service will also be put on to take people to Newmarket Train Station.

Photo: Supplied / CRL

Construction on the new Aotea and Karangahape Rd stations will also accelerate in the new year, with several long-term road closures planned around Wellesley, Victoria and Pitt streets and Beresford Square.

Work will ramp up on the upgrades of Quay St, High St and Karangahape Rd, and the new park being created in Wynyard Quarter, Wynyard Common.

Mayor Phil Goff said the work represented the greatest ever level of growth and development Auckland had ever seen.

"Is there going to be disruption? Yeah, there is - significant disruption. That's regrettable but unavoidable," Mr Goff said.

"We're going to have the Wellesley St intersection closed for nine months, Victoria St intersection will be closed - not at the same time as Wellesley St - for over 12 months. The Mt Eden Train Station will be closed for four years.

"That is going to have a disruptive effect and we're planning around that, but if you don't do those things then you don't transform this city in the way that it needs to be."

A public information campaign will get underway next year.

Summary of major closures