"Those mini-summits do not serve the cause of Darfur nor that of the Sudanese people," Sudan Liberation Movement (SLM) chief Abd al-Wahid Muhammad Nur said on Monday.
Egypt is to host a summit in the Red Sea resort of Sharm al-Shaikh on 20 April with leaders from Chad, Egypt, Libya, Nigeria and Sudan to try to find a solution to the Darfur crisis.
But Nur said he considered such summits "damaging because the Sudanese government exploits those mini-summits like a mark of support which only increases its stubbornness".
A similar five-way meeting over Darfur - also without the presence of the rebel movements - was held in Libya in October last year, but did not produce any results.
The Sudanese government crackdown on an uprising launched by rebel groups in Darfur in February 2003 has led to what the UN has described as the world's worst continuing humanitarian crisis, with tens of thousands dead and 1.6 million people displaced.