DHAKA (Reuters) - Police fired rubber bullets and tear gas to disperse armed protesters staging blockades across Bangladesh on Sunday as part of an opposition push to get an independent administration to oversee next year's general election.

Activists from the country's two main political parties hurled homemade bombs and threatened to use guns and other weapons, Reuters witnesses and local television said.

Police and witnesses said supporters of the Bangladesh Nationalist Party (BNP), led by former prime minister Begum Khaleda Zia, and its allies set ablaze about 30 buses, trucks and cars in the capital Dhaka and other parts of the country.

"We are trying to contain the battles between activists and police, which has prevented movement of vehicles and forced residents from the streets," a police officer said.

Witnesses said the highway from Dhaka to the main port of Chittagong was deserted after the road had been barricaded. Other roads around the country were also blocked.

At least two people were killed and about 100 injured, police said. Dozens of activists were detained across the country.

The political scene in Bangladesh has been dominated for decades by bitter rivals Khaleda Zia and current Prime Minister Sheikh Hasina, whose electoral campaigns have sparked violent clashes and on occasions prompted military intervention.

The two women, both in their mid 60s and who have served two terms each as the country's leader, are likely to face each other again in the next election due by end of 2013.

The BNP called for Sunday's blockade to force Sheikh Hasina to restore a system of holding parliamentary elections under a non-party caretaker administration, instead of it being supervised by the party in power.

Hasina's government over-ruled the caretaker provision in a constitutional amendment last year.

The BNP and allies including Jamaat-e-Islami, the country's largest Islamic party, want the caretaker system to be re-instated to guard against what they say would be an attempt by Hasina's Awami League party to steal the election results.

In 2007, the army was forced to intervene amid an election standoff between the two main parties.

It formed a caretaker administration after the then BNP-led government failed to hold fresh elections by the end of its parliamentary mandate. A military-led interim government organised fresh elections in 2008.

(Reporting by Anis Ahmed and Ruma Paul; Editing by Jeremy Laurence)