The party of Nigeria's president-elect Muhammadu Buhari has won governorship elections in a majority of the country's 36 states after a historic presidential win, official results have showed.

The results on Monday showed that the All Progressives Congress took control of at least 19 governor's seats following Saturday's closely-fought regional polls but could add to that tally with results from several states still pending.

President Goodluck Jonathan's People's Democratic Party (PDP) had controlled the federal and most state governments since the end of military rule in 1999, but suffered major losses during Nigeria's 2015 election cycle.

Among the victories for PDP was the oil-rich Rivers State, a key state in the Delta region from which Jonathan hails. 

Jonathan lost the presidency to APC candidate Muhammadu Buhari in elections last month that were considered the freest and fairest yet in the country.

The parties faced off again on Saturday in elections for Nigeria's powerful state governors, who control budgets larger than those of some small nations.

Voting had to be extended into Sunday in some areas in several states including Rivers due to ballot box snatching and violence. In some, polls have been delayed even longer.

The electoral commission reported 66 instances of violence at polling stations, with the highest number in Rivers and other southern states.

Source: Agencies