MANILA, PHILIPPINES -- About 250,000 people in Manila will go back into lockdown, an official said Monday, as the number of new coronavirus infections in the Philippines surges.

Residents in Navotas, one of 16 cities that make up the sprawling capital of 12 million people, will have to stay home for a fortnight, just six weeks after emerging from one of the world's longest lockdowns.

"I am not sure if this is a solution, but I am certain that if I do this the number of cases will not increase," Navotas city mayor Toby Tiangco told a radio station.

Navotas, one of the poorest areas of Manila and home to its main fishing port, has 931 confirmed cases and 59 deaths, according to local government figures.

But the number of new infections has spiked in the past two weeks.

"We have no choice but to do it because people are so stubborn," said Tiangco, referring to people flouting social distancing rules.

The order is expected to take effect on Wednesday or Thursday, Tiangco told AFP, adding the full set of guidelines was still being finalised.

Residents will be allowed to go to work, but outdoor exercise will be banned. Shops and businesses can remain open but restaurants will only be allowed to do take-aways.

Tiangco said he has asked the capital's police chief to deploy troops to enforce the orders and arrest violators.

Quarantine measures to contain the virus vary across the Philippines, but the strictest and longest lockdown was in Manila, the centre of the country's outbreak.

It shut down in mid-March and only began to reopen at the beginning of June with limited public transport and offices permitted to have skeleton staff.

Since then lockdowns have been re-imposed on several neighbourhoods as cases jumped, but the stay-at-home order for Navotas will be the biggest.

The tough measures have hurt millions of workers in Manila, which accounts for more than a third of the country's economic output.

But the relaxation of rules and the return of thousands of overseas workers have seen a surge in the number of new cases across the country.

TIGHTER RESTRICTIONS

The Philippines has the second highest number of infections in Southeast Asia, with more than 57,000 cases and 1,599 deaths.

Indonesia tops the regional rankings with more than 75,000 cases.

A record 2,539 new cases were reported on July 8 and the figure has been over 1,000 most days this month.

On Monday, the health department reported more than 2,000 fresh infections for the previous day and a record 162 new fatalities, but it included deaths that had not been counted in recent months.

Researchers from the University of the Philippines project the total number of cases could top 80,000 by the end of July.

Private hospitals Makati Medical Center and St. Luke's Medical Center said Monday they had reached full capacity for treating COVID-19 patients.

Secretary Carlito Galvez, who heads the inter-agency task force spearheading the government's response to COVID-19, said Monday restrictions would be tightened in some areas.

President Rodrigo Duterte is expected to announce details Wednesday.