ABEOKUTA, Nigeria - One of Nigeria's most powerful politicians lost his seat in the National Assembly as opposition candidates made gains against the entrenched ruling party in the oil-rich nation's first round of election, preliminary election results released Sunday showed.

Newspapers gleefully boasted headlines featuring how the polling station near the country's presidential palace went against the ruling party. House of Representatives Speaker Dimeji Bankole conceded defeat to an opposition party candidate in Abeokuta, while the daughter of former President Olusegun Obasanjo reportedly lost her Senate seat there as well in Saturday's election.

The vote widely took place without the intimidation and rigging seen in previous polls, though bombings struck the country's northeast. But whether the election will catapult the young democracy away from a history of failed polls and military rulers remains to be seen as hard-fought presidential and gubernatorial elections loom ahead.

"It's one thing to vote," said Kendy Mayungbe, a 62-year-old reading a newspaper at an Abeokuta market. "It's another thing to let the vote count."

In Abeokuta, a city of a half million people 50 miles (81 kilometres) from Nigeria's commercial capital of Lagos, Bankole acknowledged he lost as the results came in. The vote came as a shock to the southwestern city, home to some of the nation's most powerful elite families.

"For me the race was not a life and death duel," Bankole said in a statement. "Of more importance is building, maintaining and developing our democratic institution and processes as a means towards true national development and greatness."

Iyabo Obasanjo-Bello, the daughter of the former president, also reportedly lost. She was joined by the daughter of late President Umaru Yar'Adua, who lost as a ruling party candidate in a House of Representatives election in the northern state of Katsina.

Wins by opposition parties in some areas suggest a freer and fairer election for Nigeria, a country of 150 million people and a chief supplier of crude oil to the United States. Yet both local and international observers gave only caveated praise for the polls.

Project 2011 Swift Count, a coalition of trusted monitoring groups, reported isolated cases of ballot boxes being stolen, intimidation, violence and underage voting. It also noted some registered voters couldn't find their names on lists and election officials failed to post written results at 20 per cent of the polls its observers watched.

"While the election was not perfect, it provided a meaningful opportunity for Nigerians to exercise their right to vote," the group said in a statement Sunday.

Reuben Abati, a widely read columnist with The Guardian newspaper, also cautioned against immediately praising the country's Independent National Electoral Commission and its chairman Attahiru Jega. The National Assembly election had been scheduled for April 2, but Jega cancelled it just before the vote after ballot papers and tally sheets remained missing throughout much of the country.

Jega twice rescheduled the election before it was held Saturday. Even then, about 15 per cent of the National Assembly elections have been delayed again to April 26, the same day as gubernatorial elections, over misprinted ballots.

Nigeria faces two more elections, with its presidential election to be held April 16. President Goodluck Jonathan, the candidate of the ruling party, remains the prohibitive favourite, but opposition parties could pull even more votes after this weekend's performance.

That's if the country holds a credible vote.