More than 1,200 Afghans were affected by landmines last year
Three of the five permanent UN Security Council members are among a quarter of countries yet to sign up to a landmine ban treaty, according to a new report.
Landmine Action says 147 nations, more than three-quarters of the world's countries, have now signed or ratified the 1997 Ottawa Treaty, which seeks to ban landmines.
But China, Russia and the United States along with Pakistan, India and South Korea - which have a combined landmine stockpile of nearly 200 million - are among 47 countries yet to do so.
At least 20,000 people were killed or maimed by anti-personnel landmines last year, said Landmine Action director Richard Lloyd.
"The Ottawa Treaty has clearly been successful with three quarters of the world's nations now signed up to it," he said.
"But with stockpiles in excess of 200 million, and millions more still waiting to wreak havoc on the ground, we cannot afford to be complacent".
The Landmine Monitor 2003 report found that 85% of victims were civilians living in post-conflict countries.
More than 1,200 people in Afghanistan - one of nine countries to join the treaty in the last year - were affected by mines last year and 834 in Cambodia.
Chechnya suffered the highest number of casualties, at 5,695.
"Russia has signed a moratorium on exports of landmines but is still using them. Both sides in the conflict in Chechnya are using mines," said Mr Lloyd.
Landmine Action - whose work was championed by Princess Diana and is still supported by the fund set up in her memory - is calling on pro-ban governments such as Canada and the United Kingdom to pressure the likes of Russia and the US to sign up to the treaty.
"One sign of progress over the last year was that the United States did not use anti-personnel landmines in the Iraq conflict," said Mr Lloyd.
Rebel groups too are showing signs of softening. Two groups in Iraqi Kurdistan and 15 factions in Somalia signed up to an equivalent to the Ottawa Treaty.
However, the report found that at least six governments - Iraq, India, Pakistan, Russia, Nepal and Burma - used landmines over the last year, as did rebel groups in 11 countries.
Landmine Action also criticised the UK Government for continuing to argue that anti-vehicle mines equipped with highly sensitive anti-handling devices should not be covered under the treaty.
"Any mine that is capable of being accidentally detonated by a civilian is effectively an anti-personnel mine and should be banned," said Mr Lloyd.
"To argue otherwise is to ignore the devastating and potentially lethal impact of such devices on innocent people including children".