A UN committee has found that sanctions imposed against al-Qaeda and the former Taleban have had little impact on the groups' operations.
Attacks can be cheap, says the UN
The UN requires members to freeze assets of any person or group linked to al-Qaeda or the Taleban.
Members are also ordered to block suspects' passage and prevent them from obtaining arms or funding.
Although assets linked to al-Qaeda have been frozen, the report said it had "been hard to tell what this means".
"It is not clear from all reports of asset freezing, for example, what those
assets are, their value, or who owns them."
The report adds that while al-Qaeda's access to funding had been curtailed as result of international co-operation, "so too has its need for money".
Only 19 governments had recorded the presence in their countries of any person or group linked to al-Qaeda,
even though the number of places where the group is operating is thought to be much higher.
COST OF ATTACKS
Madrid bombings - less than $10,000
Bali nightclub bombings - less than $50,000
US embassy bombings in Kenya and Tanzania - less than $50,000
Attacks in Istanbul, Turkey - less than $40,000
9/11 attacks - "six figure sum"
Only 34 governments had reported freezing al-Qaeda-linked assets.
The findings of the Security
Council committee, chaired by Chilean Ambassador Heraldo Munoz,
are due to be debated on Monday.
Investigators noted most al-Qaeda attacks have involved arms not covered by sanctions.
The report gives the example of the Madrid train bombings in March, in which nearly 200 people were killed by devices made from locally-available mining explosives, detonated by mobile telephones.
It says that al-Qaeda has spent less than $50,000 (£28,000) on each of its major attacks since the 11 September 2001 hijackings.
Only the attacks on Washington and New York had required "significant funding of over six figures".
The investigators went on say that while the UN Security Council has reacted to incidents, "al-Qaeda had shown great flexibility and stayed ahead of them".
"There is no prospect of an early end to attacks from al-Qaeda," it added.
"They will continue to attack targets in both Muslim and non-Muslim states, choosing them according to the resources they have available and the opportunities that occur."
The panel said that based on evidence, al-Qaeda was trying to obtain biological and chemical weapons, as well as a so-called "dirty bomb" that would disperse radioactive material.
"There is a real need... to try to design effective measures against this threat," the panel said.
It recommends that the Security Council update its methods, which were first imposed in 1999 to reinforce international co-operation against terrorism.