Two rockets have been fired into a United Nations compound in Kabul as voting gets underway in Afghanistan's election.

A local worker was wounded in the attack, which is being described by the UN as a very minor incident. It happened around two kilometres from an election commission counting centre.

One of the first to cast his ballot was President Hamid Karzai, who was voted in nearly a year ago.

Turnout is expected to be high for the election, despite the threats and reality of violence.

One reason is this is an historic poll, the first of its kind in 30 years.

Around 12.5 milion Afghans are registered to take part, and they face a bewildering choice, with an estimated 5,800 candidates standing for 249 seats in the national parliament and 34 provincial councils.

Complicating matters further is the fact candidates are standing as individuals, not on party lists.

Many of those taking part will be women.

About a quarter of the seats in parliament are reserved for female candidates.

Security has been high in the run-up to the vote, with 20 suspected Taliban arrested in one province as they tried to plant bombs under a dam.

Just outside the capital Kabul three policemen were killed in an ambush.

PHOTO CAPTION

An Afghan man shows the ink on his finger as he prepares to cast his ballot for the parliamentary elections in Herat September 18, 2005. (REUTERS)