Mr Karzai's plan is to attract the Taliban to his side
The United Nations has removed five former Afghan Taliban officials from its sanctions list which was imposed because of alleged links to al-Qaeda.
The UN said the five would no longer be subject to international travel bans and a freeze on their assets.
Separately, German Chancellor Angela Merkel said a fixed date to pull troops from Afghanistan would be a mistake.
She was speaking with Afghan President Hamid Karzai ahead of Thursday's London conference on Afghanistan.
The UN Security Council sanctions panel "approved the deletion (de-listing) of the five entries" from its blacklist of individuals subjected to a travel ban, assets freeze and arms embargo, the UN said in a statement.
The five men are former members of the Taliban government, and were put on the UN blacklist in 2001.
This step is not sufficient, the UN should have removed a noticeable number of the Taliban names from the blacklist so a positive step would be taken to end [the] war in Afghanistan
Abdul Wakil Mutawakil Former Taliban foreign minister
They were not active insurgents and there had already been debate within the UN sanctions committee on whether to remove them from the list.
The men include Abdul Wakil Mutawakil, who was a foreign minister when the Taliban were in power in Afghanistan.
The others are:
Faiz Mohammad Faizan, a former deputy commerce minister
Shams-us-Safa, a former foreign ministry official
Mohammad Musa, a deputy planning minister
Abdul Hakim, a former deputy frontier affairs minister.
Mr Mutawakil said the move was a good start but did not go far enough.
"I consider it as restoration of my human rights," the Pakistan-based Afghan Islamic Press quoted him as saying.
"The UN should have removed a noticeable number of the Taliban names from the blacklist so a positive step would be taken to end [the] war in Afghanistan."
There are more than 140 names of suspected Taliban members with alleged links to al-Qaeda on the UN sanctions list.
Support has been growing for the notion of reconciliation with elements of the Taliban.
President Karzai is hoping to gain backing at the London conference for a plan to offer low- and medium-level Taliban fighters money, jobs and support to lay down their weapons.
Genral Stanley McChrystal: "We're here to give time and space to the Afghan people to build a nation"
Representatives of 60 nations are gathering in the UK capital to discuss strengthening Afghanistan's army and to push Mr Karzai to increase efforts to fight corruption.
Speaking in Berlin after discussions with Mr Karzai, Germany's Chancellor Angela Merkel said she agreed with his goal of having Afghan troops fully responsible for security in Afghanistan by 2014.
But she said it would be a mistake to set a fixed date for the withdrawal of German troops from the country because it would encourage the Taliban.
"We don't want to give the Taliban an excuse to go quiet and then launch a big attack," she said.
On Tuesday, she said she planned to send 500 more troops to join the 4,300 already there.
Germany's forces in Afghanistan are the third largest foreign contingent
US President Barack Obama has said he wants to start withdrawing American troops from Afghanistan in July 2011.
This year, however, the US is sending an additional 30,000 troops to Afghanistan, to reinforce the approximately 70,000 already there.
Other nations in the Nato-led coalition have contributed about 30,000 troops to provide what the Nato commander, US General Stanley McChrystal, calls "time and space" to build up the Afghan security forces.
He told the BBC he saw "no major problems" to meeting President Obama's timetable.
Mrs Merkel also said Berlin would put 50m euros ($70m; £44m) into an international fund to win over more moderate insurgents, and increase its development aid to 430m euros per year - nearly double the current level.
Meanwhile, a group of aid agencies with long experience of operating in Afghanistan has warned of a danger of growing militarisation of the aid effort there.
The eight agencies, including Oxfam and Christian Aid, said the pressure to achieve quick results had led to aid going through the international forces in Afghanistan rather than civilian channels.
Their report said foreign military projects designed to win the hearts and minds of the Afghan population were often inappropriate and exposed civilians to Taliban attacks.
This page is best viewed in an up-to-date web browser with style sheets (CSS) enabled. While you will be able to view the content of this page in your current browser, you will not be able to get the full visual experience. Please consider upgrading your browser software or enabling style sheets (CSS) if you are able to do so.