The state was supposed to get 75 lakh of vaccine doses this month and received 54 lakh till Friday, he said.
''The Covaxin stock in our state is very low. We have only one lakh and some small quantities in the hands of the districts. We were supposed to receive two tranches of a total of 2.55 lakh Covaxin which were not delivered as per schedule,'' the official said.
Till Saturday, West Bengal has received a total of 2.36 crore vaccine doses from the central government and procured at least 17.74 lakh doses, he said.
The state has vaccinated over 2.75 crore people so far and out of them, 81.9 lakh got the second dose, he said.
According to the official, the state has currently the infrastructure to administer more than 1.5 crore doses per month.
''The only constraint is getting an adequate quantity of vaccine on time,'' he said.
West Bengal Chief Minister Mamata Banerjee has urged the central government to allot at least three crore vaccine doses to the state.
Meanwhile, on Saturday, the Covid-19 toll in West Bengal rose to 18,604 with eight more deaths while the tally went up by another 730 new cases to reach 15,22,833, the health department said in a bulletin.
In the last 24 hours, 920 recoveries were registered in the state, which improved the discharge rate to 98.03 per cent.
Till Saturday, 14,92,878 people have recovered from the disease and the state currently has 11,891 active cases.
In the last 24 hours, 52,188 samples have been tested for Covid-19 taking the total number of such clinical examinations to 1,54,28,549, the bulletin added.