Last year, around 19.5 million people went on mudik, according to the government.
Curbs to allow public transport to fill only half their seats, and to limit occupation of a private car and motorcycles, were not enough to stop cases rising, Riono said.
He declined to say how many additional deaths mudik might trigger, but his group of researchers predicted last month there could be over 140,000 deaths and 1.5 million cases across Indonesia by May unless the government takes tougher action.
SHORTAGE OF VENTILATORS
Separately, modellers led by the Institute of Technology Bandung (ITB) forecast Indonesia would need 180,000 Intensive Care Units (ICUs) under its best-case scenario, which sees infections rising to 1.6 million in the country of 260 million people.
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Health ministry data in March showed Indonesia had just 8,413 ventilators, essential to treat people with respiratory illnesses. That is less than 5 per cent of ventilators required for the peak of the outbreak.
Indonesia has been attempting to get more ventilators from abroad but had found that difficult so was coordinating with companies to try to "reverse engineer" them, Industry Minister Agus Gumiwang Kartasasmita told Reuters. He hoped to have a prototype by the end of April.
The ITB modelling found that under a scenario with weaker government measures and 5.5 million cases peaking in July, 600,000 ICUs would be needed.