Pakistani prosecutors said Sunday they have appealed to the country's top court after a man was acquitted of murdering his celebrity sister over what he called her "intolerable" behaviour on social media.

Qandeel Baloch -- who was dubbed the Kim Kardashian of Pakistan -- was strangled to death in 2016 by her brother Muhammad Waseem.

Muhammad Waseem spent six years in prison but was freed last month
Muhammad Waseem spent six years in prison but was freed last month AFP / Shahid Saeed MIRZA

He had brazenly told local media that he had no remorse for the killing and was initially sentenced to life in prison.

After six years, Waseem was freed on a legal technicality that allows a victim's mother to pardon the crime.

The case was considered the most high-profile "honour killing" of recent years -- where women are murdered by male relatives for purportedly bringing "shame" to the reputation of a family.

Pakistani social media celebrity Qandeel Baloch was strangled to death by her brother
Pakistani social media celebrity Qandeel Baloch was strangled to death by her brother AFP / STR

Pakistan had passed legislation in 2016 mandating life in prison for honour killings, supposedly closing a loophole that allowed family to pardon the crime.

But Waseem, 38, was acquitted after a judge ruled the crime was not an honour killing and so, in line with Pakistan's other laws on murder, their mother was still allowed to grant his freedom.

"We have challenged his acquittal, which was granted to him on mere assumptions and technical grounds," state prosecutor Khurram Khan told AFP Sunday.

The appeal was filed on Friday, Khan added, but the top court has yet to fix a date for the hearing.

Pakistani MP Maleeka Bokhari said the Supreme Court has an opportunity to set an important precedent when the case reaches its doors.