ANALYSIS-Failing army reforms threaten Congo peace

* Government, donors failing in army reforms

* Chaotic units threaten fragile peace deals

* Situation risks undermining Kabila's future

By Joe Bavier

HOMBO, Congo, June 19 (Reuters) - The failure of efforts by Congo and its foreign backers to forge an army from former belligerents is straining the latest peace deal near to breaking point and threatens to undermine the government's authority.

Donor nations and the largest ever U.N. peacekeeping force helped organise 2006 elections meant to usher in a new era of peace and investment in the nation that has vast mineral resources but has been plagued by years of conflict.

But Congo's army remains in tatters, with foreign security sector reform plans still unimplemented and army units, cobbled together from various pro- and anti-government factions, often accused of war crimes and worsening the humanitarian crisis.

Operations begun under a deal with former foe Rwanda aimed at ending a rebellion by Congolese Tutsi CNDP rebels and rooting out Rwandan Hutu FDLR rebels have stalled. Some unpaid soldiers have mutinied, others have turned their guns on the U.N. force.