Kiwirail says a $1.1 billion revamp of Auckland's rail network will reduce waiting times between trains to no more than 10 minutes.
However, not everyone is convinced.
Auckland transport consultant Stephen Greenfield says demolishing the Kingdon Street Station, five minutes walk from the new Newmarket Station, is misguided.
He says the transport authorities are forcing Western Line trains to pull into Newmarket Station, which will add three to four minutes to the journey.
He says it will also add to congestion and introduce extra costs.
The revamp - which includes preparation for the electrification of the Auckland rail network and double tracking of the Western Line - is expected to be completed over the holiday period.
Upgrade of Wellington rail network
A further $500 million is being spent on the capital's rail network.
A third main line is being installed at the main railway station to ease bottlenecks and prepare for a new fleet of electric trains.
KiwiRail spokesperson Jenni Austin says the works are at their most intense this week, though they will take several more weeks to be fully completed.
She says it is a massive job and there's a short period of time to get it done.
"We've got track lifted up and big holes being excavated at various sites around the network.
"There's a bridge being demolished and replaced in about a five week period."
Bus replacement services are in operation for many Auckland commuters until 18 January, while in Wellington, buses are replacing trains between Wellington and Johnsonville, Petone and Tawa until 5 January.