A record number of 350,000 containers is expected to pass through Port Lyttelton this financial year, compared with 330,000 containers last financial year.
The port says container trade continues to increase with about 20% growth in the past two years.
Operations manager Paul Monk said the port is buying a fourth ship-to-shore gantry crane and is increasing its fleet of straddle carriers from 18 to 22 to keep up with the increasing demand.
Mr Monk said the investment will cost about $16 million and the equipment is expected to be onsite by the end of 2014
He said the port has been resilient, despite quake repairs expected to take up to 10 years.