DHAKA (Reuters) -- Prime Minister Begum Khaleda Zia led tens of thousands of her followers in a street march in Dhaka on Sunday, urging supporters to vote for her Bangladesh Nationalist Party (BNP) in a general election next January.

The city's transport system almost collapsed as streams of chanting and dancing Khaleda supporters took to the streets in the afternoon.

The BNP called the march to mark its founding anniversary, but revelers turned it into what amounted to an election rally.

Khaleda urged Bangladeshis to thwart efforts by opponents to disrupt the election.

"During our rule law and order has improved, economic indicators have strengthened, investment and foreign exchange reserves have peaked," she said.

At the end of her five-year rule, Khaleda is due to hand over power around late October to a caretaker administration which will supervise the election.

A 14-party opposition alliance led by Khaleda's arch rival Sheikh Hasina of the Awami League has threatened to boycott the polls unless the government implements electoral reforms before the vote.

The proposed reforms include the removal of the Election Commission chief and his deputies, whom Hasina accuses of pro-government bias.