The WHO's Bruce Aylward told the BBC hazard appraisal arrangements were set up.
He conceded that the WHO could "make a superior showing with regards to" with imparting what was being done, yet emphasized that there was no compelling reason to put off the Games.
In a public statement, 152 researchers said new discoveries in regards to Zika made it "dishonest" for them to proceed.
They additionally said the worldwide wellbeing body ought to return to its Zika direction.
The Zika infection is connected to extreme birth deformities.
Amongst February and April, Brazil enlisted more than 90,000 likely instances of Zika. The quantity of children conceived with Zika-connected deformities remained at 4,908 in April.
Dr Aylward, who heads the WHO's crisis program, told the BBC that it was at that point doing a danger evaluation program "about this ailment and the dangers it postures both to people who get and the individuals who may be accordingly uncovered".
Moreover, he said, free specialists had answered to the WHO on the ramifications of the episode for travel and exchange.
"Those are two of the careful measures that that gathering has requested and that is precisely what is being done, and obviously we need better imparted that."
What you have to know Key inquiries replied about the infection and its spread
Travel exhortation Countries influenced and what you ought to do
The mosquito behind Zika What we think about the bug
Premature birth situation Laws and practices in Catholic Latin America
The International Olympic Committee (IOC) has said it sees no motivation to postpone or move the Games in view of the mosquito-borne ailment.
Mr Aylward said that a call to put off the Games couldn't be discounted later on, however included: "All the data accessible today... recommends that the diversions should proceed."
He restated the WHO's notice that ladies who are pregnant or look to get pregnant ought not go to the Zika zone or be presented to returning accomplices who may have been contaminated.
Deferring the diversions, at this stage, would just "trade off the gigantic speculation that competitors and others have made in get ready for what ought to be an incredible event."
Zika disease in pregnant ladies has been appeared to be a reason for microcephaly and other cerebrum variations from the norm in infants.
In February, the WHO announced late flare-ups of those illnesses in Latin America and French Polynesia a worldwide wellbeing crisis requiring a unified reaction.
It said venturing up projects to destroy mosquitoes that spread the Zika infection were a need.
The letter was marked by 150 worldwide researchers, specialists and therapeutic ethicists from such establishments as Oxford University and Harvard and Yale colleges in the United States.
They refer to the disappointment of a mosquito-destruction program in Brazil, and the nation's "debilitated" wellbeing framework as motivations to put off or move the Olympics in "the name of general wellbeing".
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