And the continuing threat of terrorist violence, barely diminished after a decade of war, along with political uncertainty over the country's future, is cruelling efforts to stem the flow of people from the country, the UN's refugee agency says.

''The situation in Afghanistan remains volatile, with continuing conflict and random violence causing further … displacement,'' the agency says in its country profile.

There has been a spike in attacks on non-combatants in Afghanistan. UN Secretary-General Ban Ki-moon told the Security Council this week that terrorists in Afghanistan were increasingly targeting civilians.

Last week, 214 Afghan civilians were killed or wounded in 48 separate incidents. Two suicide attacks, one at a popular lakeside hotel near Kabul where families were eating dinner, killed 38 people.

While violence continues to drive people from Afghanistan - 35,700 formally applied for asylum last year, a 34 per cent rise on the year before - some go back, unable to find a new home, or hoping the domestic situation has improved.

Five million Afghan refugees have returned to the country in the past decade. But more than 40 per cent of these have been unable to go back to their homes because of violent attacks or threats.

Most refugees flee to Pakistan, where about 1.7 million Afghans live. But Pakistan is also a common transit country for Afghans looking to come to Australia. Many travel through Pakistan to reach Malaysia or Indonesia, from where they seek a boat to Australia.

Their passage is guided by people smugglers with contacts along the route, and to whom they pay fees, usually running to several thousand dollars.