The UN has been "partial, weak and muddled" in its approach to bloody violence in the Democratic Republic of the Congo, former international development secretary Clare Short has said.
The UN has been unable to halt clashes in the area
Ms Short, who quit the UK cabinet last week over the handling of post-war Iraq, said more UN forces should be quickly deployed to the country.
But she said she hoped increasing international concern over atrocities in DR Congo would act as a catalyst for effective UN action.
Tony Blair told MPs on Wednesday that the UK was considering what support it could provide to a new UN force being planned for the country.
The prime minister said he had spoken to UN Secretary-General Kofi Annan over the issue earlier this week.
There are concerns over the potential for genocide in DR Congo after civilians fleeing into Uganda reported widespread atrocities by ethnic militias.
Those fears have risen after the discovery by UN workers of the bodies of more than 230 people killed in clashes between rival militias in the town of Bunia.
Ms Short told BBC Radio 4's Today programme that it was vital that DR Congo's new government - agreed in a peace deal aimed at ending its five-year civil war - is installed soon.
But she said the UN operation in DR Congo had been "less effective than it could have been".
"Instead of absolutely focusing on getting a government that brings together the three factions that were fighting - and then we can start to build a national army and help people of the Congo to start to develop the resources of their country - it has been rather partial, weak and muddled."
Talking later to BBC News Online, Ms Short said there was agreement at the UN's headquarters that the UN operation in DR Congo "has been weaker than it could have been and efforts have been made to strengthen its leadership and management".
She said: "Congo is a vast country and the peace process has been complicated.
"The UN operation in the country has not been as focused or effective as it could have been.
"And some neighbouring countries see it as biased."
The clashes in the area around Bunia erupted soon after the 9,000 strong Ugandan forces withdrew from Bunia about two weeks ago, as part of the peace deal in DR Congo.
Two groups, Hemas, traditionally cattle-raisers, and Lendus, predominantly farmers, have been in conflict for centuries for land and other resources in the area.
The rivalry has become more bloody because the Ituri district around Bunia is rich with gold.
Neighbouring nations involved in the civil war - Uganda and Rwanda - armed both sides as proxy militias.
A party of French military observers is now in Bunia to investigate the possible deployment of a multi-national force.
And the European Union said on Monday it was considering a UN request to send peacekeeping troops.
France has been asked to lead this force and provide a battalion with up to 1,000 troops, but has insisted that other nations join the force and the deployment be for a limited period.
Militia leaders, meanwhile, say they will treat any French troops who go to Bunia as enemies.
A Hema group which controls Bunia, the Union of Congolese Patriots (UPC), says the French back Congolese President Joseph Kabila, who the UPC says is helping the Lendus.
The Lendus are the majority in Ituri but some accuse former colonial power Belgium of favouring the Hemas.
Ms Short said that while events in the country were horrific, she was hopeful that the media attention would help to speed up the UN response.
"At least out of this is coming all this international attention which I hope will lead to a strengthening of Monuc (the UN operation in DR Congo) in the east," she said.
"I am hopeful that good will come out of bad.
"Congo has been misgoverned and plundered for years. It has 50 million people, but no roads and no schools.
"It is a heavily-indebted poor country and relief can come with the peace process to help the people build a decent country.
"I will take decades but there is a great job to do. It is the heart of Africa and if it could come to peace it would stabilise the country and the countries around it."
Ms Short said the UK had honoured its commitments in the region in terms of helping Rwanda rebuild after the genocide almost 10 years ago.
But she warned: "There won't be safety for the people of Rwanda or Burundi, where you have got this same ethnic poison that comes from the colonial times, without a proper settlement in the Congo.
"It is do-able. It just needs more higher level international attention and then bringing into being a new government in the Congo...
"It can be moved forward very quickly with just a bit more international attention with Britain playing its proper role.
"We have been strongly involved in the Congo and I am sure my successor and others will continue to be engaged."
And Mr Blair told MPs it was "very important that the (UN) force is properly led and properly supported because otherwise we will revisit...the terrors of a decade or so ago".
Ms Short said the arming of rival factions by other countries was "exacerbating historic tensions" in the region.
She said militias responsible for the genocide in neighbouring Rwanda in 1994 were still in the east of DR Congo and the installation of the new government could lead to them being disarmed and their leaders sent to face charges at the International Criminal Court.