In a statement from its regional headquarters in Manila the WHO said the measles outbreak which has plagued the country for almost a year will continue to spread unless more children are vaccinated.
It did not say how many youngsters the disease had killed this year.
The WHO would declare the Philippines measles-free "only if every village vaccinates at least 95 percent of its children," said Soe Nyunt-U, the organisation's representative in the Philippines.
"Failure to do so will result in the return of an estimated 6,000 deaths a year of Filipino children from this preventable disease."
The Philippines is halfway through a nationwide anti-measles campaign.
But with two weeks left, only 20 percent of the targeted 8.9 million children aged nine months to three years have been vaccinated, the WHO said.