The interim government had asked Ethiopian troops to support it against the Islamic Courts after the group gained widespread control of the country earlier in the year.
"Negotiations would include the opposition as well as the TFG [Transitional Federal Government], to determine problems and find solutions," Adaw said.
When challenged on the recent suicide attack on Ali Mohamed Gedi, the interim Somali prime minister, Adaw denied that the Islamic Courts had organised it.
"I do not know who attacked the prime minister, the Islamic courts is a peaceful movement. We denounce violence, and we are against violence," he said.
The suicide bomber struck outside Gedi's house in the capital, Mogadishu, killing seven people, witnesses said. Gedi was not hurt.
Adaw accused the Ethiopians of being "terrorists" and said that the TFG in Somalia had no power.
"The Ethiopians are terrorising the Somali people and the Somalis are defending themselves... When the Somali people are being killed day and night, and they resist and the world is calling this terror, then this is not right.
The US links the Islamic Courts Union to al-Qaeda, but Adaw denied that the organisations were linked, and said that al-Qaeda was not even present in Somalia.
"Ethiopia is occupying Somalia and the transitional government in Somalia has no power at all"
Ibrahim Adaw, former head of foreign relations with the Islamic Courts Union in Somalia
"We have nothing to do with any other organisations. The US military has said that al-Qaeda never had any base in Somalia. It's a contradiction to say al-Qaeda is present in Somalia and then say that they never had a base in Somalia.
"Somalia is a country without a government. No one knows who comes in or who goes out, so the Islamic courts is not responsible for who is inside Somalia.
"There is no government; Ethiopia is occupying Somalia and the transitional government in Somalia has no power at all."
Meles Zenawi, the Ethiopian prime minister, made a surprise visit to Somalia on Tuesday, where his troops have been fighting in support of the weak Somali interim government.
Zenawi met Gedi and Abdullahi Yusuf, the president, before holding separate talks with Mogadishu residents and tribal elders.
Abdi Haji Gobdon, a Somali government spokesman, said Zenawi made a promise to withdraw Ethiopian troops once peace in Somalia was restored.
Ethiopia has said repeatedly that it plans to withdraw its troops, but Ethiopian soldiers continue to patrol the capital, coming under frequent attack.
On Tuesday, a Somali official, Ali Mahdi Mohammed, said the government still planned to hold a national reconciliation conference in Mogadishu on June 14 despite the unrest.