Iran on Thursday announced 149 new deaths in 24 hours from the novel coronavirus -- one every 10 minutes -- as calls mounted for the government to take stricter measures against the disease.

The latest toll was a daily record for Iran, where the overall toll of 1,284 dead makes it one of the countries worst hit by the pandemic.

But Deputy Health Minister Alireza Raisi said the daily number of new cases had fallen. A total of 18,407 people have contracted the disease in Iran, with 1,046 new cases confirmed in the past 24 hours, he said.

However, health ministry spokesman Kianoush Jahanpour painted a grimmer picture, tweeting that the rate of new infections had risen to 50 an hour and "one (patient) dies every 10 minutes". But "in 11 provinces" out of 31, "the number of infections has decreased because people have followed our guidelines", Raisi said, reiterating calls for Iranians to stay home.

Tehran province had the highest number of new cases, with 137 reported, followed by the central province of Isfahan with 108 and Gilan in the north with 73. Jahanpour appealed for Iranians to "make a conscious decision concerning travel, days out and family visits during Nowruz", the Persian New Year holiday.

The Nowruz holiday, which this year is from Friday until April 3, usually sees millions of Iranians travel to visit family. Iran also said it would free "around 10,000 prisoners" in an amnesty to mark Nowruz.

That would "reduce the number of prisoners in light of the sensitive situation in the country", said judiciary spokesman Gholamhossein Esmaili. For several weeks, Iranian authorities, who have so far refused to impose confinement or quarantine measures, have asked the population to refrain from travelling and to take the virus "seriously".

Several provinces have ordered the closure of hotels, and Iran has announced the rare shuttering of four important Shiite holy sites. In an open letter to President Hassan Rouhani, published on state television's website, five former health ministers urged the government to "strictly bar unnecessary movement and travel between provinces".

Failure to do so would amount to "playing with people's lives" and risk the disease spinning out of control, they warned. "We must disrupt the chain of contacts between healthy people and the sick."

A prominent professor at Tehran's Sharif University of Technology, Alinaqi Machayekhi, on Thursday gave projections of the disease's advance in the country. In the case of "responsible behaviour", the disease could cost 12,000 lives out of a total of 120,000 infections, he said.

But a worst case scenario with no coercive measures, with Iran's medical services overrun, could see the death toll shoot up to 3.5 million out of a population of 81 million, he said. He did however stress that his models had not been validated.