A spokesman for the country's telecommunication authority said the order had been received from the ministry of information technology and was being implemented.
It comes after a row over Pakistan's blocking for nearly a fortnight last month of the Facebook website due to blasphemous content.
"The major websites which will be monitored for anti-Islam content include Yahoo, Hotmail, MSN, Bing, Amazon and YouTube," the spokesman told AFP.
He added that the government had also ordered the blocking of 17 webpage links containing blasphemous content. The links include pages within YouTube, Islam Exposed and Jehad.org
A high court earlier this week ordered the government to block access to nine websites including Google, Yahoo, YouTube, Amazon, MSN, Hotmail and Bing for showing material against "the fundamental principles of Islam and its preaching".
Judge Mazhar Iqbal of Lahore High Court announced the order in the eastern city of Bahawalpur in response to a petition filed by retired civil servant Siddique Mohammad.
Pakistan shut off Facebook for nearly two weeks last month in a storm of controversy about a competition to draw the Prophet Mohammad [PBUH] and has restricted access to hundreds of online links because of blasphemy.
Islam strictly prohibits the depiction of any prophet as blasphemous and the row sparked comparison with protests across the Muslim world at the publication of satirical cartoons of Islam’s Prophet [PBUH]in European newspapers in 2006.
When a Facebook user decided to organize the blasphemous competition to promote "freedom of expression" it sparked a major backlash among Islamic activists in the South Asian country of 170 million.
In the wake of the controversy, Pakistan blocked some 1,200 individual web pages and Uniform Resource Locators (URLs) to limit access to "blasphemous" material.
Facebook together with YouTube accounts for up to 25 percent of Internet traffic in Pakistan. The country briefly banned YouTube in February 2008 during a similar protest against blasphemous cartoons of the Prophet Mohammed [PBUH].
Source: AFP