Afghanistan's government has backed away from a proposal to reintroduce public stoning as a punishment for adultery after the leak of a draft law stirred up a storm of international condemnation.

The president, Hamid Karzai, said in an interview that the grim penalty, which became a symbol of Taliban brutality when the group were in power, would not be coming back.

"It is not correct. The minister of justice has rejected it," he told Radio Free Europe, days after the UK minister Justine Greening urged him to prevent the penalty becoming law.

Afghanistan's penal code dates back over three decades. The government is drawing up a new one to unify fragmented rules and cover crimes missed out when the last version was written, such as money laundering, and offences that did not even exist at the time, such as internet crimes.

The justice minister presiding over the reform is an outspoken conservative who last year denounced the country's handful of shelters for battered women as brothels.

As part of the process, a committee tasked with looking at sharia law came up with draft legislation that would have condemned married adulterers to the slow and gruesome death; unmarried people who had sex would be flogged.

But after several days of silence in the face of growing international outcry, the justice ministry said in a statement that although stoning had been proposed it would not appear in the new legislation because there was "no need to regulate the issue".

The country's penal code already encompasses sharia law, but some controversial aspects of traditional punishments such as stoning have never been put on the books in Afghanistan.

"The legality of the crime and punishment is fully addressed and there is no need to regulate the issue in the new code. So, the ministry of justice does not intend to regulate it in the new draft code," the statement said.

Rights groups who first highlighted the draft law warned that although the government's quashing of the proposal was good news, its emergence in the first place was a sign of how fragile gains in human rights over the last decade had been, particularly for women.

Although stoning is listed as a punishment for adulterers of both sexes, in countries where it has been used in recent years women have often appeared on the execution ground alone.

As foreign troops head home before a 2014 deadline for the end of combat action in Afghanistan, and political attention fades with it, many activists fear that years of painstaking progress are at risk of being swept away.

"Of course it's a huge relief that the government appears eager to disown this proposal now, but this is not an aberration that appeared out of the blue," said Heather Barr of Human Rights Watch.

"It is just the latest in a long string of efforts to roll back women's rights over the last half year, many of which have been successful. It is time for donors to wake up and realise that if there is not constant pressure on the Afghan government to respect women's rights, there will be no women's rights."