Pakistan's army on Saturday denied any involvement in the abduction of a writer and rights activist who was kidnapped for several hours this week.

Gul Bukhari, a dual Pakistani-British national, has been a vocal critic of the powerful Pakistani military, and its alleged meddling in politics, on social media and in her articles in the run-up to the July 25 general election.

"We have nothing to do with it. I think this incident should be investigated thoroughly," Major General Asif Ghafoor said.

Ghafoor said he had checked with every intelligence agency working for the army whether Bukhari had been detained by them shortly after the abduction was reported.

Bukhari was on her way to record a television programme late on Tuesday in the eastern city of Lahore when her vehicle was intercepted and she was taken away by unidentified men, her husband and media colleagues said.

The activist has also defended ex-prime minister Nawaz Sharif, who clashed with the military before he was forced out of office last year by the Supreme Court.

After her release, Bukhari, herself the daughter of an army general, said on Twitter she was well and asked for privacy.

In her first comment since here abduction, Bukhari said in a tweet early on Sunday, without naming anyone: "Is there any shame? Any ethics, any grace? You just picked me?"

Pakistani media organisations have alleged growing censorship by the military in the run-up to the election, while rights groups have denounced the kidnappings of several social media activists over the past year as attempts to intimidate and silence critics of Pakistan's security forces.

Last year, five bloggers went missing for several weeks. Four were released and fled abroad, with at least two later alleging that they were tortured by a state intelligence agency.