ISLAMABAD (REUTERS) - Tens of thousands of Pakistanis are thronging coronavirus vaccination centres daily after officials announced penalties for the unvaccinated, including blocked cellphones and barred access to offices, restaurants, shopping malls and transport.

Queues for inoculations stretched more than 1km in some locations this week, in response to measures designed to help slow a Delta variant-fuelled surge in infections that has put pressure on Pakistan's poor health infrastructure.

In a country that has a long anti-vaccination history, health workers said many in line were more afraid of the restrictions - some started on Aug 1 while others kick in on Aug 30 - than the health threat of Covid-19. That perception was supported by people queueing who spoke to Reuters.

"I'm personally not scared of the coronavirus," said banker Abdul Rauf as he stood in line at a vaccination centre in southern Karachi, with his mask pulled down to his chin.

"Our salaries will be stopped, our SIM cards will be blocked, so all these things are out there, so that's why I got my second dose done."

Pakistan has a long anti-vaccination history - Pakistan and neighbouring Afghanistan are the only countries in the world where polio is still an endemic disease - and Covid-19 hesitancy has been high.

Out of a population of 220 million, only 6.7 million people have been fully vaccinated, according to the National Command and Operations Centre, a military-run body that oversees the Covid-19 operations.

Pakistan's federal government announced late last month it would ban staff from entering public offices, schools, restaurants, transport, shopping malls and air travel without vaccination certificates.

The announcement prompted an immediate rise in vaccination rates, which hit one million a day last week.

"I came here and obtained this card after getting the vaccination, merely because I have to travel abroad, and I will not be able to travel without doing this," said Mr Mohammad Atiq Qureshi, a lawyer in Karachi.

The local government in the southern province of Sindh went even further, warning that it could withhold the salaries of government servants and block people's cellphone SIM cards unless they had the required certificates.

"There is a small percentage who are coming to get a shot for fear of the disease or for their safety, but the majority of the people are coming for fear of having their business closed... or the youngsters who want a shot for fear that their SIMs will be blocked," said Dr Jamila, a health worker at one of the vaccination centres.

Pakistan on Thursday (Aug 5) reported 5,661 new Covid-19 cases, the highest single-day number in more than three months, and 60 deaths. Around 70 per cent of the new cases are caused by the Delta variant and more than 4,000 people are in critical condition, officials said.

The country has recorded more than one million infections and around 23,600 deaths since the beginning of the pandemic.

Health Minister Faisal Sultan said the requirement of a vaccination certificate had "helped to encourage vaccination".

Mr Murtaza Wahab, a Sindh provincial government spokesman, said work was under way on the logistics of blocking cellphones.

Anecdotal reports suggested that some businesses had already begun restrictions on service.

"We were denied McDonald's at a rest area on a motorway if we couldn't show a text message to prove that we are vaccinated," said Mr Moiz Raja, who travelled from Islamabad to eastern Lahore city last week.