Imran Khan declared victory in Pakistan's rancorous general election on Thursday as rivals alleged he had benefited from widespread vote rigging.

The cricketer-turned-opposition politician appeared set to be prime minister after unofficial forecasts gave him a commanding lead.

The 65-year-old given the nickname 'Captain' by supporters looked just short of a full majority, but was expected to find small coalition partners easily and declared he had been given a popular mandate.

In a speech broadcast from his Bani Gala estate outside Islamabad, he restated his populist promises, vowing a new Pakistan where he would crackdown on corruption and build an Islamic welfare state.

However there were fears last night of political paralysis, or even violence after his unexpectedly strong performance at the polls was rejected by rival parties.