Lyttelton Port of Christchurch has lodged an application for resource consents to Environment Canterbury to deepen its shipping channel by up to 4 metres, so larger vessels can call over the full tidal range.
"We want to secure consents so when the time is right we can begin work as soon as our customers require it," said chief executive Peter Davie.
"We expect the dredging programme to take around 8-12 months to complete and it will cost around $25 million for each metre of additional draught created."
The existing channel ends approximately 1km inside the harbour heads. It would extend about 4km beyond the harbour heads in the proposed plan.
The dredged sediment would be deposited at a site approximately 6km from Godley Head, where the water is 20m deep.
The port believed the sediment would not affect the Banks Peninsula bays.
Ports around the country are preparing for the eventual arrival of larger container ships. The largest ships currently calling in New Zealand carry 4100 containers.
There are concerns that too many ports will dredge when larger ships are likely to call at only one or two ports.
