Top Iranian officials initially downplayed the risks posed by the virus outbreak, before recently urging the public to follow measures like wearing masks and avoiding non-essential travel.

Iran has recorded daily death tolls of above 430 over the past five days.

The Iranian Health Ministry said on Saturday that the total number of confirmed cases has risen to above 840,000.

The new lockdown measures, which include shuttering most businesses, shops, malls, and restaurants, include Iran's largest cities of Mashhad, Isfahan, and Shiraz.

Iranian authorities have designated the nearly 160 towns and cities affected as hot spots because these urban centres have the highest daily per capita positive coronavirus test results.

On Saturday, Iranian President Hassan Rouhani in a televised speech urged people to follow the measures to help "lessen the death toll."

He added that the government plans to supply cash subsidies to Iran's 30 million poorest people for four months to help them to manage the economic fallout from the new outbreak.

The latest round of restrictions to stem the outbreak came as a spat among top Iranian health officials led to the resignation of at least two officials.

Iran has avoided the full lockdowns seen in other countries as it struggles to keep its faltering economy alive in the face of crushing US sanctions.

President Donald Trump reimposed sweeping sanctions on the country after withdrawing from Iran's nuclear deal with world powers in 2018.

Australian Associated Press