A 14-party opposition alliance organized Tuesday's march as part of a six-day nationwide campaign to press for a revised electoral roll and resignation of the chief election commissioner ahead of general elections in January 2007.
Authorities deployed nearly 4,000 riot police, paramilitary troops and members of a special anti-crime force to prevent any violence during the protest march, Shahidul Islam, joint commissioner of Dhaka Metropolitan Police, said earlier.
An Associated Press reporter at the scene estimated the number of protesters at 10,000. Police said they were not able to give an estimate because participants were joining the protest along the route.
A helicopter and security cameras also kept watch on the marchers, but there were no immediate reports of clashes or violence.
Police also restricted traffic along the march route in the northern part of Dhaka, the national capital of 10 million people, the AP reports.
In recent months, opposition parties have staged a series of anti-government strikes and street protests, many of which turned violent with fierce clashes between demonstrators and security forces.
The opposition alliance accuses chief election commissioner M.A. Aziz of favoring Prime Minister Khaleda Zia's government. It also claims that a new voter list contains fake voters and excludes many known opposition supporters. Aziz and the government have denied the allegations.
Zia is due to end her five-year term in October and transfer power to a nonparty caretaker administration, which will hold a fresh election within the next three months.