Papua New Guinea is the first country to receive a new patrol boat under an Australian initiative to assist 12 countries.
The Australian foreign minister Julie Bishop gave details at a speech to Pacific Islands Forum foreign ministers in Fiji.
Julie Bishop said the ceremonial keel laying for the first boat was done in Western Australia at the end of July.
She told a meeting in Suva that the first boat is scheduled to be completed in October next year and will be given to Papua New Guinea.
She said Australia planned to build 19 boats to be supplied to 12 countries.
The announcement was tied to Canberra's efforts to step up its engagement in the Pacific.
Two decades ago Australia gifted 20 patrol boats to Pacific countries to bolster maritime security.