The hackers attacked websites of some key ministries on the day the country celebrated its 70th Independence Day.
The sites hacked included Ministry of Defence, Ministry of Climate Change, Ministry of Inter-provincial coordination, Ministry of Water and Power, Ministry of Information Technology and others.
An official of the Ministry of Information Technology said the attack was carried out by a group calling themselves "LuluSec India". The hackers posted pro-India material on the web pages of hacked websites.
Several websites are still not functional. There was no formal reaction by the government so far.
It is not the first incident of cyber-attack by hackers targeting the Pakistani government websites. Such attacks have occurred in the past also.