WHO Director General Tedros Adhanom Ghebreyesus said the manufacturers Abbott and SD Biosensor had agreed with the Bill & Melinda Gates Foundation to "make 120 million of these new, highly portable and easy-to-use rapid Covid-19 diagnostic tests available over a period of six months".
He told a news conference in Geneva the tests were currently priced at a maximum of $5 each but were expected to become cheaper.
"This will enable the expansion of testing, particularly in hard-to-reach areas that do not have laboratory facilities or enough trained health workers to carry out tests," Tedros said.
"This is a vital addition to the testing capacity and especially important in areas of high transmission."
In other international Covid-19 developments:
According to researchers at Johns Hopkins University, there have been almost one million confirmed deaths from Covid-19 in the world. But the number is likely to be an underestimate as testing rates in many countries remain low, with virus-related deaths not being recorded.
The number of new COVID-19 cases in the United States has risen for two weeks in a row in 27 out of 50 states, with North Carolina and New Mexico both reporting increases above 50 percent last week, according to a Reuters analysis.
Quebec, the Canadian province hardest hit by the novel coronavirus, reported another sharp increase in daily infections on Monday, amid media reports that Premier Francois Legault would announce new restrictions for Montreal and capital Quebec City
The British government tightened restrictions on socialising in parts of northeast England in response to high and increasing Covid-19 infection rates in the region. From Wednesday, residents in seven areas including urban centres such as Newcastle, Gateshead, Sunderland and Durham will be barred from socialising indoors with people from outside their household or strictly defined social bubble.