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.

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, 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.

The national COVID-19 task force reported 17,669 coronavirus cases and 165 deaths on Thursday, both record highs. It said 21 of the fatalities had died at home.

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.

There are more than 37,000 hospital beds, including in makeshift field hospitals, in Bangkok and surrounding provinces, according to the Bangkok Metropolitan Administration.

Thailand won plaudits for containing the coronavirus for most of last year, but authorities have struggled to halt the wave of cases starting in April that has taken total infections to 561,030, with 4,562 fatalities.