The World Health Organisation is encouraging countries in the Pacific to increase their surveillance of dengue fever in order to determine the precise numbers of people affected.
The WHO's Dr Eric Nilles says the region is on a heightened state of alert because of an outbreak of Type 2 in the Marshall Islands and the Federated States of Micronesia.
"There is a surveillance system throughout the Pacific that the WHO office has put in place with SPC. We are encouraging countries to increase the surveillance to include dengue-like illness into that surveillance - it's a weekly reporting system so we are able to determine whether or not we are seeing an increased number of cases in the Pacific and if so where exactly."
Dr Nilles says since the 19th of December, there have been 1,225 clinical cases,150 hospitalisations but no deaths in the Marshall Island.
He says in the FSM there have been 833 clinical cases, 159 hospitalisations and two deaths.