Saif-ul-Mulook's freed Asia Bibi, who spent a decade on death row in Pakistan in a blasphemy case. (File)

The Pakistani lawyer who saved a Christian woman convicted of blasphemy from the gallows left the country on Saturday, saying his life was under threat.

Saif-ul-Mulook's latest victory saw the freeing of Asia Bibi, who spent nearly a decade on death row, after the Supreme Court overturned her sentence on Wednesday.

The decision sparked protests across the country, with major roads blocked in Lahore and Islamabad as religious hardliners called for the death of the judges and those who helped acquit Bibi.

"In the current scenario, it's not possible for me to live in Pakistan," the 62-year-old told AFP before boarding a plane to Europe early Saturday morning.

"I need to stay alive as I still have to fight the legal battle for Asia Bibi," he said.

Blasphemy is a massively inflammatory charge in Muslim-majority Pakistan, where even unproven allegations of insulting Islam and its Prophet Mohammed can provoke death at the hands of vigilantes.

On Friday night, the Tehreek-e-Labaik Pakistan party (TLP), which has largely led the demonstrations, announced an end to mass protests after reaching a deal with the government.

A five-point agreement seen by AFP, signed by both parties, said the government would not object to an appeal of the verdict, filed earlier in the Supreme Court.

When asked about the Islamist outcry, Mulook said it was "unfortunate but not unexpected".

"What's painful is the response of the government. They cannot even implement an order of the country's highest court," he said, adding that "the struggle for justice must continue".

According to the agreement, which came after a failed first round of talks, legal proceedings will follow to impose a travel ban on Bibi and stop her leaving the country.

"Her life would be more or less the same, either inside a prison or in solitary confinement for security fears" until a decision on the appeal, said Mulook.

The deal was criticised by local media and the country's oldest newspaper Dawn called it "another surrender" in an editorial on Saturday.

"Yet another government has capitulated to violent religious extremists who neither believe in democracy, nor the constitution," it read.

The TLP, founded in 2015, blockaded the capital Islamabad for several weeks last year calling for stricter enforcement of Pakistan's controversial blasphemy laws.

That protest forced the resignation of the federal law minister and paved the way for the group to poll more than 2.23 million votes in the July 25 general election, in what analysts called a "surprisingly" rapid rise.