Ports of Auckland said it had been granted consent from Auckland Council to deepen the port's shipping channel.
The consent allows the channel to be deepened from 12.5 metres to between 14 metres and 14.2 metres.
The company said the consent would safeguards Auckland's vital international supply line by allowing larger container ships to enter Auckland's port, such as 366-metre-long New Panamax vessels with a maximum draft of 15.2 metres.
Tidal windows will be used to make best use of the natural water depth and keep dredging to a minimum.
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"The Covid-19 lockdown highlighted the essential role Auckland's port plays in the economy," Ports of Auckland's chief executive Tony Gibson said in a statement.
"A deeper channel will ensure Auckland's port can continue that essential role for decades," Gibson said.
Ports of Auckland, which is owned by Auckland Council, asked for the application to be publicly notified, so that people could have their say on the project.
Over two hundred submissions were received, with the main concern raised being the disposal of dredged material.
Ports of Auckland said it would work with key submitters to look for ways to reduce or eliminate the need for sea disposal.