Defence Secretary Gotabhaya Rajapaksa is the president's brother
Sri Lanka's defence secretary has rejected the Tamil Tigers' offer to enter a democratic process after their military defeat by government forces.
In an interview with the BBC, Gotabhaya Rajapaksa said the LTTE rebels could not be trusted to give up "terrorism".
The rebels had said they would give up violence after their leader was killed in recent fighting in the north-east.
Later on Tuesday the UN Human Rights Council meets to discuss how to provide aid to thousands of displaced people.
The BBC's Ethirajan Anbarasan was taken by the Sri Lankan military to two camps housing tens of thousands of displaced people. He said conditions in one camp were very basic, with people complaining of a lack of water, proper food and sanitation.
At another camp - also run by the military - conditions were better, although still cramped.
Mr Rajapaksa - the most senior civilian official in charge of the war against the Tamil Tigers - told the BBC in a wide-ranging telephone interview that he was "not interested in LTTE at all."
He said: "I do not believe the LTTE can enter a democratic process after years of their violent activities." He added that there were "enough democratic Tamil political parties in the country" to represent the Tamil minority.
On Sunday, speaking to the BBC's Tamil service, senior rebel spokesman Selvarasa Pathmanathan said they would now use non-violent methods to fight for the rights of the Tamils and had agreed to enter a democratic process to achieve their aims.
Mr Rajapaksa also said the work of government forces was not yet over as they had to recover weapons hidden by the LTTE in the northern and eastern regions.
"Some people think that the army's task is over... it is not. The entire area has to be de-mined and then we have to look for any remnants of the LTTE hiding in the jungles," Mr Rajapaksa said.
He has also appealed to Western nations to dismantle the LTTE's overseas network and hand over their local leaders, who he said were trying to purchase arms and ammunition for the group.
On reports of intrusive checks against Tamils in the capital Colombo in recent weeks, Mr Rajapaksa said the Tamil community was not being singled out.
He said everyone - including government officials and politicians - was being stopped at checkpoints for security reasons.
"It is not our aim to continue with these security procedures. These checks will be eased once normality gradually returns to the country," he said.
The Tigers' defeat has almost brought to an end their 26-year fight for a separate Tamil homeland.
Most of the senior leadership of the Tamil Tigers is thought to have been killed in fighting with government forces in recent weeks.
About 280,000 Sri Lankan civilians have been displaced, posing a huge problem for the government and the international aid agencies.
Only a few days ago, visiting UN Secretary General Ban Ki-moon had called for a process of national reconciliation that would fully address the legitimate aspirations of the Tamils in Sri Lanka.
The special session in Geneva will consider two resolutions.
The first, proposed by Switzerland and backed by European countries, calls for aid agencies to be given unimpeded access to all those in need, including the 300,000 people housed in government-run camps.
The UN has complained that the government has been blocking humanitarian aid.
The second resolution, from Sri Lanka itself, supported by China and India, calls on the UN to co-operate with the Sri Lankan government in providing humanitarian aid.
It also asks the international community for financial support to rebuild the country.