Global anti-mine programmes face a budget shortfall of $565m in 2010, meaning humanitarian mine clearance will move at a much slower pace than last year.
UN officials at an international review conference on the Mine Ban Treaty in Colombia on Friday said projects planned in 27 countries to clear mined areas were in jeopardy.
UN projects currently work on destroying mine stockpiles, providing assistance to mine survivors and running mine-risk education programmes in local communities. It will cost nearly $600m next year.
"We are unlikely to make that funding in a year," Maxwell Kerley, head of the UN Mine Action Service told reporters at the start of the conference in the Colombian city of Cartagena. "It means it will take longer to get the job done."
About five per cent, or $24m, of the total proposed budget has been secured to date. Delegates at the review conference are urging aid donors to match their contributions made last year to fund future projects.
Last year $518m was spent on mine action, with the bulk of funding allocated to mine clearance operations. The European Union, the US and Japan are the world's biggest donors to anti-mine programmes.
Afghanistan, home to the world's highest rate of annual landmine casualties, receives the largest share of international mine action aid, over $100m last year, followed by Sudan.
"Full donor support for these programmes will contribute to ongoing efforts to consolidate peace initiatives and facilitate post-conflict reconstruction," Kerley said.
He added that with the right levels of funding and security in place, significant progress can be made in clearing mines in Afghanistan within six years.
Last year, landmines and explosive remnants of war claimed nearly 5,200 casualties across 70 countries.