PKNIC (domain name registry for ccTld .pk) has desigenated .gov.pk for Federal ministries of the Government of Pakistan and departments that come under federal government of Pakistan's control or Geodiction. In certain situations .gov.pk can be registered for high level Provincial Departments which is one of it's kind in that particular province but name of the province should be prominent in domain name for example Punjab-Education.gov.pk or Punjab-Police.gov.pk etc. Only real government bodies / institutions can register a gov.pk domains after proper verification.
Top Level Domain name is called Tld, there are many Tld can be used to register domains. Other than generic Tlds there are country level domain names called ccTlds,, .pk is a ccTld for Pakistan. PKNIC is SRS (Shared Registry System) for all .pk domains, its working since 1992 and is managing all Pakistani domain names since then. Domains can be registered directly with pknic or by authorized pk domain re-sellers, like most of the other Tlds and ccTlds .pk domains are also open to anyone for registration, however registration fees are different for local Pakistani customers and non Pakistani or International customers. Minimum registration or renewal period for .com.pk, .net.pk, org.pk, .edu.pk and gov.pk domains is 2 years.