The five were all members of the ousted Taliban government.
Wakil Ahmed Muttawakil, the former Taliban foreign minister now taken off the list, called on the UN and the US to remove all the names on their blacklists.
"[Not only] the UN list, but the US blacklist should also be reconsidered, as the names are not specified and the number is unknown. We can say that the number of those wanted by the US is between 100 and 1000,” Muttawakil said.
The other four ex-ministers removed from the UN list are Faiz Mohammad Faizan, Shams-US-Safa, Mohammad Musa, and Abdul Hakim.
The UN blacklist was established under UN Security Council Resolution in 1999 for the purpose of overseeing implementation of sanctions imposed on Taliban-controlled Afghanistan for its support of Osama bin Laden's al-Qaeda network.
Under the resolution, UN member states are required to impose sanctions on any individual or entity associated with al-Qaeda, bin Laden and/or the Taliban.
The list contains about 500 names, including 142 linked to the Taliban.
Karzai hopes to win Western support at the London conference for a plan to offer money and jobs to persuade Taliban fighters and other armed groups to lay down their weapons.
He has said there are "thousands and thousands and thousands" of moderate Taliban who needs to be reintegrated in the Afghan society.
Al Jazeera's David Chater, reporting from the Afghan capital, said talks with the group Hezb-e-Islami had been held at the Maldives Islands on January 23-24.
"We've had confirmation from the finance ministry that those talks were going ahead. Gulbuddin Hekmatyar [the group's leader] sent his son and two son-in-laws to the meeting.
"They [government representatives and Hezb-e-Islami] decided to go set up two delegations ... One will be headed by Hekmatyar's son and the other one will be headed by the deputy head of the peace and reconciliation commission. He will go and see President Karzai and Hekmatyar's son will go and see the Taliban."
Our correspondent said a Taliban leader had been due to attend the meeting but dropped out in the last minute citing health reasons.
Habibullah Fawzi, the former Taliban ambassador to Saudi Arabia, said Karzai wants to negotiate with the Taliban, but has failed failed to do so because the Afghan government’s viewpoints differ from those of the US and foreign forces.
"The Afghan government could have started a dialogue with Taliban movement if it had had a unified stance with the international community," he told Al Jazeera.
"However, they have lost this opportunity, and in stead of initiating talks, the government and foreign forces started to strike Taliban fighters in several areas and on the borders and take them to detention centres like Guantanamo and others.
"This has forced Taliban to wage war."