BANGKOK, July 16 (Reuters) - Thailand reported on Friday (Jul 16) a daily record of 9,692 COVID-19 infections, taking total cases to 381,907 since the start of the pandemic, as authorities struggle to tackle the country's biggest wave of infections so far.

The COVID-19 task force also reported 67 more COVID-19 deaths, bringing the total number of fatalities to 3,099.

AstraZeneca has asked Thailand to extend the timeline for the delivery of 61 million doses of its COVID-19 vaccine by five months, deputy health minister Sathit Pitutacha said on Thursday.

The delay is due to a slow production ramp-up at AstraZeneca's local manufacturing partner, which had initial production and delivery issues.

Thailand had earlier said that it was considering imposing limits on exports of locally manufactured AstraZeneca COVID-19 vaccine to fight its own outbreak.

The country's main vaccine rollout started last month and only about 5 per cent of its more than 66 million people have been fully vaccinated.

Three more Thai islands - Samui, Tao and Phangan - opened to vaccinated foreign tourists on Thursday as part of Thailand's push to revive its battered tourism industry.

Under this scheme, tourists must stay at an approved hotel on Samui for a week and can leave their accommodation on day four.

They will have to produce a negative COVID-19 test before being allowed to venture to Tao or Phangan after their first week.

Thailand launched its "sandbox" scheme on Jul 1, allowing vaccinated travellers to visit Phuket island. Tourists do not have to quarantine in a hotel but cannot leave Phuket for two weeks.