BANGKOK (REUTERS) - Thailand's Phuket will ban travel from the rest of the country from Aug 3-16 to try to stop a surge in coronavirus cases from spreading to the resort island, but overseas visitors will be largely unaffected, the foreign ministry said on Thursday (July 29).

Phuket is at the heart of efforts to revive Thailand's tourism industry, a major revenue earner that has been devastated by the pandemic.

Since July 1, tourists fully vaccinated against Covid-19 have been allowed to move freely on the island, with no self-isolation on arrival, an initiative dubbed the "Phuket sandbox".

Thai Foreign Ministry spokesman Tanee Sangrat said the new travel rules will restrict movement to Phuket from elsewhere in Thailand, meaning foreign visitors who stay on the island will not be affected.

Tourists who have stayed on Phuket for more than 14 days will be allowed to leave for other parts of Thailand and can re-enter Phuket only if they have international flights booked from the island's airport, Mr Tanee said.

An order signed by Phuket's provincial governor said exceptions would also be made for medical supplies and personnel and supplies of fuel, money and food.

Operating hours have been restricted for some venues on Phuket and some have been ordered to close as authorities try to limit any impact from the rise in infections across the country.

Thailand has in the last few months been struggling with its worst Covid-19 outbreak since the start of the pandemic, driven by the highly contagious Delta variant, first detected in India.

Thailand reported on Thursday a daily record of 17,669 new coronavirus infections, bringing the total number of cases to 561,030 since the start of the pandemic last year.

The country also reported a record 165 Covid-19 deaths, also a daily record, bringing the total number of fatalities to 4,562.

Hospitals in Thailand's capital Bangkok and the surrounding provinces are running out of capacity due to the surge in infections. More than 1,200 people are waiting for hospital beds and over 6,000 have called a hotline in the last week requesting treatment, health authorities said.

"We don't know where to put the sick people anymore, the ER (emergency room) units in many hospitals have to be temporarily closed because they no longer have bed spaces," Department of Medical Services head Somsak Akksilp told a news conference.

Meanwhile Thai volunteers on Wednesday turned a cargo warehouse at Bangkok's Don Mueang Airport into a 1,800-bed field hospital for Covid-19 patients with less severe symptoms, as the country deals with its biggest outbreak to date.

Workers drilled walls for toilet installations and set up beds and blankets.

"This is a level 1+ field hospital where it can receive a large number of patients, who have less severe symptoms," Dr Rienthong Nanna, director of Mongkutwattana Hospital, told Reuters.

"But if patients' conditions deteriorate, they will be moved to our other field hospital called Pitak Rachan (Protect the King) Field Hospital," he added.

Dr Rienthong, a retired major-general and an ultra-royalist leader, said the field hospital was not up and running yet as more preparations were needed.

The number of infections will continue to climb and more field hospitals will be needed, he added.