Election authorities in Afghanistan have postponed a parliamentary election due this year.

Western diplomats welcomed the decision to push the election to 18 September from 22 May.

It is hoped that the change will provide time to implement changes designed to prevent a repeat of fraud that marred President Hamid Karzai's re-election as president last year.

The date also means the election would fall after the traditional summer fighting season.

That will give an expanding NATO-led force more time to improve security in southern areas, where Taliban fighters kept voters from last year's polls.

Independent Election Commission member Zekriya Barakzai said the postponement was due to 'problems and constraints to get the proper budget, and also security concerns, logistical obstacles and also to improve the electoral procedures'.

Western countries are trying to avoid a repeat of last year's election fiasco, in which a UN-backed investigation discarded nearly a third of votes cast for Mr Karzai as fake.

They had been hoping a postponement would be announced before an international conference on Afghanistan's future in London later this week, where the early date was set to be an irritant.

UN Secretary General Ban Ki-Moon and representatives of many of the 43 nations involved in the Nato-led International Security Assistance Force will meet on Thursday to discuss the process towards handing control to Afghan forces and withdrawing allied troops.

The UN is holding tens of millions of dollars earmarked for Afghan elections in an account, but diplomats have said they will not release the money without reforms.