Hundreds of thousands of Islamic worshippers gathered in eastern Pakistan this week amid the novel coronavirus pandemic, ignoring government warnings that such events could propagate the disease.

Organisers late Thursday curtailed the annual Tablighi Ijtema congregation, which had drawn people from across the country, but cited rainy weather as the cause.

The early closure came after about 250,000 people had already congregated in camps near Lahore since Wednesday for the five-day festival.

"Most of the people have returned to their homes but still tens of thousands of people are here. They will return today," one of the event's organisers Ehsanullah, who goes by one name, told AFP on Friday.

Pakistan has only recorded 21 confirmed cases of the novel coronavirus and no deaths, but officials have tested fewer than 500 potential cases in the country of about 215 million, where health care is frequently inadequate.

Many countries are advising against large gatherings in a bid to slow the spread of the highly communicable virus. Some nations -- like France and Italy -- have banned them altogether.

The federal government has yet to enforce nationwide measures to contain a possible outbreak, leaving provinces to act independently. Organisers of the Tablighi Ijtema were free to ignore government advice to postpone.

"The government asked us to cancel the gathering because of the coronavirus, but our elders and organisers decided that the gathering will proceed as planned," Ehsanullah said.

The movement was founded by religious scholars more than five decades ago and focuses exclusively on preaching Islam.

It usually sees hundreds of camps and sub-camps set up on a dusty site outside Lahore to accommodate people from across Pakistan, giving the gathering a festival feel.

Schools in three of Pakistan's four provinces are closed for March and authorities are conducting basic screenings of passengers arriving by air from overseas.

Prime Minister Imran Khan was set to meet with his national security team later Friday to discuss the global coronavirus crisis.