The warning from planning minister Asad Umar comes as many in the country continue to ignore guidance on social distancing, hygiene and other measures to tackle the disease.

Pakistan currently has confirmed nearly 140,000 cases of COVID-19, with the death toll approaching 2,700. 

Authorities have ramped up testing but this nonetheless remains limited, so real numbers are thought to be higher.

"Expert estimates say the number of confirmed cases could go up to 300,000 by the end of June if we keep on flouting SOPs (standard operating procedures) and taking the problem lightly," said Umar, who is helping coordinate the government's coronavirus response.

"We fear the number of confirmed cases could go up further to 1.2 million by end of next month," he told reporters in Islamabad. 

After initially lagging infection rates in Western nations, Pakistan and other South Asian countries are experiencing a surge in cases.

Pakistan's increase comes after people violated government restrictions and thronged mosques and markets -- mostly without masks and gloves -- during Ramadan and ahead of the Eid festival last month.

Since the start of Pakistan's outbreak in March, Prime Minister Imran Khan opposed a nationwide lockdown of the sort seen elsewhere, arguing the impoverished country could not afford it.

Instead, Pakistan's four provinces ordered a patchwork of closures, but even those restrictions have now been lifted.

Umar said hotpsot areas such as Lahore are now subject to "smart" lockdowns in which authorities attempt to track coronavirus patients and limit who they come into contact with.

"The government has decided to go for smart lockdowns by tracking hotspots and then sealing them. This will start from Punjab province," Umar said.

Authorities in Islamabad already locked down one neighborhood after tracking 200 confirmed coronavirus cases in just one day on Friday.

Hospitals across Pakistan say they are at or near capacity, and some are turning COVID-19 patients away.