Officials say 49 pregnant women have tested positive for Zika in New York City since April, and one baby has been born with microcephaly due to the mosquito-borne virus.
Overall, more than 3,400 at-risk pregnant women have been tested under the city's Zika action plan.
Officials say most people who tested positive in the nation's largest city were infected while travelling to Zika-affected areas, with a small minority getting it via sexual transmission.
Mayor Bill de Blasio said on Tuesday that the city has committed $US21 million ($A27.4 million) to protect New Yorkers from Zika. He and other politicians, including fellow Democrat US Rep. Carolyn Maloney, called on Congress to approve $US1.9 billion in emergency funding.
Federal health officials say there have been 420 Zika cases in New York City.
