Mice given experimental Zika vaccines were protected when exposed to the virus but it will be years before a finished vaccine is available for humans.

Mice given a single shot of one of two experimental Zika vaccines were completely protected when exposed to the virus one to two months later, a promising sign that similar vaccines under development for humans will protect against Zika, US researchers said on Tuesday.

"This is an encouraging first step in Zika vaccine design and pre-clinical testing," said Professor Adrian Hill, director of Oxford University's Jenner Institute, which did not conduct the mouse study but is also developing Zika vaccines.

Separately, US scientists said they have developed a model of the Zika virus in monkeys, a close proxy for human disease.

The studies advance efforts in fighting the mosquito-borne Zika virus, which has swept through the Americas and Caribbean, and has been linked to thousands of cases of microcephaly, a rare birth defect, in Brazil, as well as to neurological disorders.

On February 1, the World Health Organisation declared Zika a global health emergency.

"With diseases spread by biting insects, such as Zika, standard quarantine measures are useless, so stopping an outbreak in its tracks requires a vaccine-led approach," said Dr Derek Gatherer, a lecturer in the division of biomedical and life sciences at Britain's Lancaster University.

In the mouse study, published in the journal Nature, a team led by Dr Dan Barouch of Beth Israel Deaconess Medical Center and Harvard Medical School tested two different vaccine candidates in a strain of mice that develops Zika symptoms.

Mice given either type of vaccine were 100 per cent protected from Zika after a single shot.

Unvaccinated mice that were exposed to the virus all developed symptoms of Zika.

The team also showed that antibodies taken from immunised mice could be used to protect other, unvaccinated mice, offering proof that the antibodies produced by the vaccines were specific to Zika.

"We need to be cautious about extrapolating data from a mouse model into humans," Barouch said.

But the fact that the vaccines protected mice and that their antibodies protected other mice from Zika was grounds for optimism over the development of a Zika vaccine, he said.

At least 15 companies and academic groups are racing to develop Zika vaccines, according to the WHO.

Oxford University's Hill stressed that there are still years of testing needed before a finished vaccine will be available for humans.

In another advance, researchers at the University of Wisconsin reported on Tuesday that they have successfully infected rhesus macaques with an Asian strain of the Zika virus that is currently circulating in the Americas. The study, published in the journal Nature Communications, shows that monkeys - which have immune responses similar to humans - can be used to study Zika.