The Commonwealth Ocean Acidification Action Group Workshop includes more than 30 scientists and officials from many countries, including 18 in the Commonwealth.
Participants, including from the United Kingdom, Australia, the US, and the Pacific Islands, aim to better counter the impacts of ocean acidification.
The three-day workshop ends today, and is the action group's first activity.
New Zealand last year volunteered to champion this group as part of its support for the Commonwealth Blue Charter - an agreement by all 53 Commonwealth countries to solve ocean-related problems collaboratively.
Prof Cliff Law leads Niwa's Oceans-Climate Interactions programme and teaches at Otago.
Such acidification could "significantly impact marine ecosystems and economies'', both here and elsewhere.
The "collective power of the Commonwealth working together'' would be "crucial'', he said.
Dr Christina McGraw, of the Otago chemistry department, chairs the New Zealand Ocean Acidification Community (NOAC).
Ocean acidification would not stop in the short term but we could "mitigate for it''.
New Zealand was a world leader in this field, and our scientists had begun, in 2006, to assess the chemical and biological effects of Ocean Acidification, including in our waters.
NOAC researchers began as a group of Otago scientists, in botany, chemistry and marine science, as well as Niwa researchers.
Otago leaders initially included the late chemistry researcher Prof Keith Hunter, and botanist Dr Catriona Hurd, she said.
Scientists say that increased absorption of carbon dioxide in sea water could harm coral, lobsters, and some shellfish.