A New Zealand-led multinational military exercise, Tropic Twilight, will be held this year in Tonga's Ha'apai group of islands.
It will include military personnel from the United States, China and France as well as Tonga's armed forces.
New Zealand Defence Minister Gerry Brownlee said the benefits of such exercises were seen earlier this year in Fiji with the multi-country response to Cyclone Winston.
As part of the exercise, Pangai town and the villages of Lotofoa and Faleloa will benefit from water storage improvements and the construction of a public toilet block.
An environmental health team will also be carrying out a mosquito eradication programme aimed at reducing diseases such as dengue and zika.
