Internet services will be partially restored in India's Kashmir region from Saturday after a five-and-a half-month government-imposed blackout but social media will remain blocked, local authorities said.

Prime Minister Narendra Modi's government imposed a communications blackout in early August when it stripped the portion of Kashmir it controls – the country's only Muslim-majority region – of its partial autonomy.

India also imposed a curfew, sent in tens of thousands of extra troops and detained dozens of Kashmiri political leaders and others, many of whom remain in detention, drawing criticism abroad.

Internet access will be restored later on Saturday but only to 301 government-approved websites that include international news publications and platforms such as Netflix and Amazon.

"Access shall be limited only to the whitelisted sites and not to any social media applications," the Jammu and Kashmir home department said in a notification.

Mobile phone data access will also be restored but limited to slower second-generation (2G) connections, the department added.

India is the world leader in cutting internet services, activists say. Internet access was also temporarily suspended in other parts of the country during recent protests against a new citizenship law.

Since August freedom of movement in heavily-militarised Kashmir has been gradually restored as has cellphone coverage, but apart from at a handful of locations there has been no regular internet access.

This made life even harder for the region's seven million inhabitants and hit the local economy hard.

Mr Modi's government said that the blackout was for security reasons, aimed at restricting the ability of armed militants – who it says are backed by arch-rival Pakistan – to communicate.

The Supreme Court criticised the government earlier this month for the move, calling it an "arbitrary exercise of power".

The court also said that having access to the internet "is integral to an individual's right to freedom of speech and expression".

Kashmir has been divided between India and Pakistan since independence in 1947, and has been the spark of two wars and numerous flare-ups between the two nuclear-armed foes.

A bloody insurgency against Indian rule that has raged in the scenic Himalayan region for decades has left tens of thousands dead, mostly civilians.