Umaru Yar'Adua has only given one radio interview since becoming ill

Nigeria's forthcoming election could be held three months earlier than scheduled if electoral reforms are adopted, officials have announced.

The election is due next April but one reform proposes bringing it forward to allow time for legal challenges before the next president is sworn in.

Rescheduling the poll would also end uncertainty caused by the ill-health of President Umaru Yar'Adua.

Politicians are considering changes proposed after a flawed 2007 vote.

Electoral commission head Maurice Iwu said the presidential poll would either be held on 22 January or 23 April 2011.

Mr Yar'Adua's term of office expires in May but he is not expected to stand again.

He went to Saudi Arabia for medical treatment in November last year and, despite returning to Nigeria recently, he has not been seen in public since.

This has left a political vacuum and various factions are jockeying for power.

In his absence, Vice-President Goodluck Jonathan has been installed as acting leader.

But the ruling People's Democratic Party has said its candidate in the next election will be a northerner - ruling out Mr Jonathan.

The BBC's Caroline Duffield in Lagos says reform is crucial if Nigeria is to avoid another cycle of violence and vote-rigging next year.

But opposition politicians have complained that the government diluted the proposals before they were sent to parliament.