The World Health Organisation says there is a heightened risk of measles being brought into Pacific countries.
Several countries in close proximity to Pacific nations have reported measles outbreaks, including Australia and New Zealand.
The WHO said that means there was an increased risk of the virus being imported into Pacific countries inadvertently.
The UN children's agency UNICEF said vaccination is the best protection against measles.
It said travellers uncertain about their measles vaccination status should get at least one dose of a measles vaccine two weeks prior to travel.