New York Governor Andrew Cuomo said the state's new confirmed Covid-19 cases are predominantly coming from people who left their homes to go shop, exercise or socialise and not from essential workers.

"That person got infected and went to the hospital or that person got infected and went home and infected the other people at home," he said during his daily news conference on the coronavirus.

State data showed that the number of new cases statewide has fluctuated between 2,100 and 2,500 per day.

The number of new cases decreased to 2,419 today from 2,762 on Friday.

Cuomo said he theorised last week that new cases were coming from essential workers.

"That was exactly wrong," he said. "The infection rate among essential workers is lower than the general population and those new cases are coming predominantly from people who are not working and they are at home."

The state's budget director, Robert Mujica, said officials expect to "learn a lot more" about the genesis of new cases from contact tracing over the next week.

The state just began contact tracing, which will involve several hundred people, he said.

Cuomo said the five regions of New York that have already opened were required to have a certain number of tracers proportionate to their populations.

"The tracing operation is tremendously large and challenging," he said.

Statewide, the outbreak is ebbing, with coronavirus hospitalizations falling to 6,220, more than a third of the level at the peak one month ago, state data showed.

In the five regions where restrictions were eased on Friday,in central and upstate New York, construction and manufacturing work was allowed to resume, and retail businesses offering kerb side pickup or in-store pickup for orders placed ahead were allowed to reopen. A broader pause on activity in New York City and elsewhere was extended until at least 28 May.

New York, along with the nearby states of New Jersey,Connecticut and Delaware, will partially reopen beaches for the Memorial Day holiday weekend on 23-25 May, Cuomo has added.

He warned on Saturday that with an increase in economic activity, New Yorkers should expect an increase in coronavirus cases.

"We don't want to see a spike," he said.

"It depends on how people react and it depends on their personal behavior."