Coins from Oceania sounds very exotic because we know that some tribes used shells as main currency. The shell money is still in use to some extent in the Solomon Islands and Papua New Guinea.
Most dominant currency in the Pacific region is Dollar (New Zealand, Australia, United States) and Franc (French overseas territories).
Here is a full list of countries that has own currency: American Samoa, Australia, Cook Islands, Fiji, French pacific territories, French Polynesia, Hutt River, Kiribati, Marshall Islands, Nauru, New Caledonia, New Zealand, Niue, Palau, Papua New Guinea, Pitcairn Islands, Samoa, Solomon Islands, Tokelau, Tonga, Tuvalu, Vanuatu.
