The commercial sales of Sputnik V began over the weekend, with vaccination sites in the southern city of Karachi saying they had already sold out, reported TRTWorld.
Pictures of queues outside the hospital late into the night were shared on social media.
Pakistan is currently offering free vaccines to frontline healthcare workers and people over the age of 50, but the drive has thus far been slow, and last month the country allowed commercial imports by the private sector for the general public.
Those still not eligible for the government's free vaccination wait in long queues at vaccination sites in Pakistan to get vaccinated despite the USD 80 (12,000 Pakistani rupees) cost for a pack of two doses as the country allows private sales of the Covid-19 vaccines.
Despite the cost, a number of centres offering the shot reported long queues, with some in Karachi waiting in line for close to three hours. Most in the queue were young Pakistanis still not eligible for the government's free vaccination, reported TRTWorld.
While the private sale of vaccines has begun, the government and importers are still locked in a pricing dispute.
Pakistan initially agreed to exempt imported vaccines from price caps, but later rescinded the exemption and said it would set maximum prices.
One pharmaceutical company, which had already imported 50,000 doses of Sputnik V, took the government to court, where it won an interim order allowing it to sell it until pricing is decided, reported TRTWorld.
The number of patients now in critical care has reached 3,568, the highest since the pandemic started, a cabinet minister, Asad Umar, said on Twitter.
Pakistan has thus far reported 687,908 infections and 14,778 deaths, reported TRTWorld. (ANI)