About 70 people joined the protest, the third in two weeks calling for more political freedoms and an end to an emergency law that allows indefinite detentions.
Though small, the demonstrations could gain traction ahead of a parliamentary poll later this year and a 2011 presidential vote that might mark an end to Mubarak's 29-year rule.
Hundreds of police stood watch on Tuesday's protesters, who included the Sixth of April Youth movement and political opponents to Mubarak's National Democratic Party (NDP).
The protest came two days after a lawmaker loyal to Mubarak said demonstrators should be shot at.
"I would have questioned the Interior Ministry for being soft on these outlaws ... Do not use water hoses to disperse these outlaws, shoot at them directly," NDP member Nashaat Al-Qasas told Egypt's parliament. Qasas later backed away from his statement and top NDP official Safwat el-Sherif said the party backed Egyptians' right of expression and condemned all calls for violence or shooting.
Sherif also said he trusted the police's ability to deal with wisdom and restraint, state news agency MENA reported.
Protests have been rare in Egypt but briefly gained momentum around the first multi-candidate presidential vote in 2005, when Washington was pushing for more democracy in the Middle East.
Rights advocates say security forces have used rubber bullets and tear gas to quell protests in the past, methods they say are meant to crush dissent and keep the government in power.
The independent Al-Shorouk newspaper had also quoted Hamid Rashid, an aide to the interior minister, as saying that "the law permits police and security forces to use force and open fire on protesters if they disrupt national security." He said protesters broke the law by taking to the streets on April 6, when security forces beat and detained some of them.
An emergency law instated after the assassination of President Anwar Sadat in 1981 gives authorities scope to detain people indefinitely under the banner of national security.
Washington has criticized Cairo's handling of the protesters, but Egypt, one of the biggest recipients of US foreign aid, has dismissed the comments as interference.
While the NDP is expected to win a huge majority in parliament, Mubarak has not said if he will run again. Even if he steps down, many Egyptians say the 81-year-old, who recently underwent surgery, will try to hand power to his son, Gamal.
Mohamed ElBaradei, former head of the UN nuclear watchdog, could shake up the race if he runs.
Ayman Nour, an opposition politician who was imprisoned for alleged forgery after challenging Mubarak in 2005 polls, said Qasas should be tried for inciting violence.
