There is a growing push in the Arab world to have men responsible for so-called honour killings treated as murderers by the courts.

Every year hundreds of women are killed by their husbands or brothers or another male family member for supposedly bringing shame on their families.

In many countries the honour killers are given leniency. Many men are not charged, or they spend only a few days or weeks in custody.

But Palestinian human rights groups have recently drafted their own amendments to have them treated as murderers.

Khaled Mahmoud, 21, admits beating his sister to death last year in the West Bank.

"She has made very wrong decisions," he said.

"I started drinking then I got crazy. When I saw her I beat her. I smashed her head to the wall."

His sister Asmaa - not her real name - was 23, a university student, and engaged to be married to another Muslim.

As brother and sister they were close, yet Mahmoud says she made the unforgivable mistake of sleeping with another man, a Christian, and brought enormous shame on the family.

"I was telling her that she should stay away from him and she shouldn't talk to him because he was playing," Mahmoud said.

"He wasn't serious with her and he is bragging about what he was doing. I was so ashamed with my sister."

Mahmoud says it is hard to describe how he felt after killing his sister.

"I don't say that I wish I hadn't killed her, but I say I wish she hadn't done that," he said.

"I am really sorry for what happened, but I think even if I'm in the same situation now after this experience and she does the same thing, I would kill her again."

Mahmoud says he found a note belonging to his sister with several phone numbers and rang one to find it was a clinic that restores a woman's virginity through surgery.

He says that was the final straw.

"She was violating rules of the society. Why has she done that?

"She didn't have the right to do that. She shamed our family."

On average in the West Bank, about 20 men a year like Mahmoud kill a sister, daughter or even their mother because they claim she has brought shame on the family.

Some women are killed if they are considered promiscuous, have an affair, or even if they are victims of rape or incest.

"I don't think if anyone betrays his family (they) can be trusted by anyone else," Mahmoud said.

He says his views are representative of most people in the West Bank.

Mahmoud spent six days in custody. He was never charged and does not see himself as a murderer.

"It wasn't my fault, and I haven't done anything wrong," he said.

"I overreacted but I don't think that it makes me deserve jail for a long time."

'Killing is killing'

But human rights groups, non-government organisations and virtually every minister in the Palestinian government is demanding change so others like Mahmoud are treated as cold-blooded murderers.

Ashraf Hayyeh from the Palestinian Women's Centre for Legal Aid is one of the strongest advocates for reform.

"Killing is killing, whether it's for honour or anything," he said.

"And if someone kills that way they should deal with it as murder. He should be sentenced to at least 15 years' jail."

There is, however, one major obstacle to change.

The Palestinian penal code, in the West Bank at least, is a Jordanian law drafted 50 years ago.

To change it the Palestinian government needs to abolish that law and draft its own.

But since the militant group Hamas refused to take part in elections due last January, the Palestinian Legislative Assembly is effectively paralysed.

Until there is a new election, men like Mahmoud will continue to be let off the hook for what most countries would say is cold-blooded murder.