A crowded street in Zanzibar's capital, Stone Town. (Photo Courtesy Issa Yussuf)

In Tanzania, the offshore archipelago of Zanzibar held a referendum Saturday which is likely to mean that a coalition government is formed.

The referendum seeks approval for a constitutional change that would create two vice-president positions to be shared between the parties that come first and second in parliamentary polls.

That would almost certainly mean the leading party, the Revolutionary Party (CCM), sharing power with the Civic United Front, which has regularly claimed to have won elections and accused its rivals of rigging the polls.

The change takes place ahead of a general election in October and is a bid to prevent the clashes that marred the two previous elections.

Voting went peacefully, according to correspondent Salim Sayed Salim, although it may not be as high as the 90 per cent which is often reached in elections - believed to be the highest level in sub-Saharan Africa.

Results are expected within 36 hours.