More than 12 children suffering from the infectious disease have been admitted to several state-run hospitals in the province.
The deaths of two children were reported by hospitals in Lahore, the capital of Punjab. One death each was reported in Layyah, Mianwali, Chakwal and Wazirabad.
According to a health department official, the dead and ailing children had either not been immunised or were partially immunised as far as diphtheria was concerned.
"Diphtheria spreads among babies through sneezing and coughing. Teams have been sent to the hospitals to administer anti-diphtheria serum to the affected children to prevent more deaths," the official, Javed Akram, said.
The health department is facing an acute shortage of the serum.
"We have a stock of vials of serum for only 22 children," Akram said.
The department is likely to face a severe crisis if more patients come to government hospitals, he said.
According to an inquiry ordered by Punjab's Director General of Health Services, some 22 diphtheria-related cases were reported in 2011 and 48 in 2010 but the number of deaths due to the disease over the two years could not be ascertained.
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