More than 2000 troops from New Zealand and overseas will invade South Canterbury from Monday in the largest military training exercise the country has ever hosted.
Operation Southern Katipo, which runs until 29 November, is aimed at testing the Defence Force's ability to mount a medium-scale operation involving land, sea and air forces.
The operation scenario revolves around the fictitious Pacific Island country of Mainlandia, where international troops have been deployed to restore order after a period of ethnic violence.
The operation will mostly take place at Timaru's port and airport but will also stretch south to Waimate and west to Tekapo.
Two New Zealand navy ships and 11 aircraft will take part, along with troops from nine other countries including Australia, Britain and the United States.
More than 200 troops, backed by 60 military vehicles, took part in the first phase of the exercise in Wellington on Friday.
The exercise aims to test the capability of the defence force to mount a medium scale amphibious operation.
It was cancelled in 2011 because of the Christchurch earthquake.