SINGAPORE - The recent surge of Covid-19 cases in Indonesia was not unexpected.

Despite a government ban, official figures show that at least 1.5 million people, mostly from the capital Jakarta, had travelled to their home towns to celebrate the Hari Raya Aidilfitri holidays last month in an annual exodus known locally as mudik.

"It's all our fault. The government has gone all out to remind us to stay at home, not to mudik, but we still went ahead any way. This is the consequence," Coordinating Minister for Maritime Affairs and Investment Luhut Pandjaitan said at a virtual conference recently.

The numbers are worrying.

Indonesia remains the worst-hit South-east Asian country by far, with 1.96 million cases, including more than 54,000 deaths.

Huge clusters have emerged in a number of regencies on the populous Java island, with new variants, including the virulent Delta variant first detected in India, showing up.

On Friday (June 17), the health authorities reported 12,990 new cases, the highest daily rise since February, led by Jakarta with 4,737 cases, West Java with 2,791 cases and Central Java with 1,331 cases.

Jakarta Governor Anies Baswedan has warned that the capital - a city of 11 million people which is the epicentre of the outbreak, will enter a "critical phase" if the current situation goes out of control.

Epidemiologist Dicky Budiman from Australia's Griffith University said the situation is likely as bad, if not worse, outside Jakarta but is hard to measure due to poor data.

"We start with very poor data and poor understanding of the current situation... Seeing this as a Jakarta problem is very wrong and dangerous," he told The Straits Times.

Calls are growing for a lockdown to curb the virus spread as hospital bed occupancy shot up to 75 per cent in Jakarta from 45 per cent last week.

Dr Dicky said there is a "big probability" that Indonesia may face a similar situation as in India, in terms of a rise in the number of cases and deaths which would burden the healthcare system, he said.

"Lockdown should be one of our weapons, or a hammer, to contain the Delta variant," he added.

The World Health Organisation on Thursday (June 17) also called for large-scale social restrictions, stating in its situation report: "With increased transmission due to variants of concern, urgent action is needed to contain the situation in many provinces."

The World Bank's Indonesia Economic Prospects report released on the same day made similar recommendations.

Besides accelerating a vaccine roll-out, Indonesia should improve testing, tracing and isolating cases, as well as impose adequate mobility restrictions.

It noted that Indonesia's free vaccine roll-out has begun to lag behind some of its large Group of 20 (G-20) peers despite an earlier and stronger start.

"The pandemic risks still loom large, with cases increasing significantly in June. Indonesia remains vulnerable to new waves driven by more transmissible strains as experienced by other countries as well as potentially higher mobility and viral transmission during festivities," the report said.

Indonesia's vaccination drive, which started strong in January, has been languishing due to logistical issues and mismanagement, said Mr Achmad Sukarsono, associate director and lead analyst for Indonesia at Control Risks.

"There is no light at the end of the tunnel just yet," he said in a June 1 outlook report. "With delays in distribution and cases of vaccine theft by officials, placing too much hope on the vaccination drive will lead to disappointment."

But the Indonesian government has never been keen on nationwide lockdowns due to fears of economic repercussions. A localised lockdown is an option the government is willing to take if the situation escalates significantly, said Mr Achmad.

Vaccination, it appears, remains a silver bullet solution, with the government planning to ramp up the daily inoculation rate to 1 million doses a day.

President Joko Widodo, or Jokowi as he is better known, has ordered the administration of Jakarta to vaccinate 100,000 people a day to reach herd immunity by August. He admitted it is "an ambitious target but we have no other options but to do it".

Professor Hasbullah Thabrany, public health expert and chief of the Indonesian Health Economic Association, said that while there is no room for complacency, the current infection figures must be taken in perspective as Indonesia has a huge population of 270 million people.

"In terms of percentage, 10,000 cases in Indonesia is far smaller than 10,000 in Malaysia or the Philippines," he told The Straits Times, adding that the current spike is still lower than the peak in January, with daily cases of around 15,000.

He said: "I believe we can keep the situation under control."