Tens of thousands of Egyptians packed city centres across the country to demand faster reforms and voice frustration at what they regard as foot-dragging by military rulers and government officials.

Anger has been building among ordinary Egyptians and activists over the time taken to prosecute Hosni Mubarak and former officials charged with corruption and killing demonstrators during the uprising that toppled the president.

Most political organisations including the Muslim Brotherhood, Egypt's most organised grouping, backed calls for the protest, called 'the Revolution First', which took aim at Mohamed Hussein Tantawi, who heads the ruling army council.

Cairo's Tahrir Square, centre of the uprising in February, was decked with red, white and black Egyptian colours in one of the biggest rallies since Mubarak's downfall.

Analysts say the political group, harassed and repressed under Mubarak, is best positioned to benefit from the timetable for transition outlined by the army, with a parliamentary election in September.

Presidential hopeful Mohamed ElBaradei, a former UN diplomat, has said that there were some 'unrealistic expectations' as Egyptians shook off decades of repression and he said it would take time to deliver wholesale change.

Former Arab League Secretary General, Amr Moussa, another presidential hopeful, joined the protesters in Tahrir.

Activists handed out surveys and one question read: 'How do you assess the performance of the military council?' Some protesters showed off their forms where they had ticked a box saying: 'performance getting worse.'

Many Egyptians believe the health problems reportedly afflicting Mubarak are a ploy by army generals to avoid bringing the former air force commander to trial.

Public frustration has also been fuelled by court rulings this week clearing three former ministers of graft charges and another court decision to free on bail 10 policemen charged with killing demonstrators.