BRUSSELS, Belgium - More than 2,500 trade unionists have been murdered in Colombia in the last 12 years and an international commission should be created to investigate, a global labour federation said on Tuesday.

The International Confederation of Free Trade Unions (ICFTU) said in a report that the United Nations' International Labour Office (ILO) should appoint the commission at a meeting next week, despite opposition from the Colombian government.

"It is public knowledge that the trade union rights situation in Colombia is disastrous," the Brussels-based ICFTU, which groups trade unions representing 124 million workers in 143 countries, said.

"Since 1987, over 2,500 trade union activists and leaders have been murdered there. Many more have been kidnapped, tortured, threatened with their lives and persecuted in numerous ways, while thousands have been forced to flee their town, their region, or even the country itself."

Thirty trade unionists had been killed between January and July of this year, it said.

The ILO's governing body is due to decide whether to establish a commission of inquiry at a meeting starting on November 16.

The ICFTU said Colombia had shown a "complete inability to stop this carnage" and dismissed what it called a diplomatic offensive by the Colombian government to try to avoid the commission being appointed.

Colombia is embroiled in a war in which an estimated 20,000 guerrillas control up to half of the country, according to estimates by U.S. defence officials. Rival paramilitary groups are also battling for greater territorial control.

The ICFTU said the Colombian government had suggested the appointment of a commission would torpedo peace negotiations with the guerrillas, but that Colombian and international trade union organisations considered this argument "null and void."