Zimbabwe's elections were free and peaceful, the two leading African observer groups have said.
African Union mission head Olusegun Obasanjo dismissed complaints of fraud, while another observer urged all parties to "accept the hard facts".
A local monitoring group said earlier the poll was "seriously compromised".
President Robert Mugabe's party is claiming victory in the election, which has been dismissed by Prime Minister Morgan Tsvangirai as a "huge farce".
On Wednesday, voters were choosing a president, 210 lawmakers and local councillors. The results must be declared by the Zimbabwe Electoral Commission (Zec) no later than five days after voting day.
No presidential figures have been announced but the first official results from national assembly elections show that Mr Mugabe's Zanu-PF party is taking an early lead. However, the seats announced were mostly in Mr Mugabe's rural strongholds, correspondents say.
Zanu-PF spokesman Rugaro Gumbo predicted that Mr Mugabe, 89, - who is running for a seventh term - would get at least 70% of the vote in the presidential poll.
"We are expecting a landslide victory," he was quoted as saying in Zimbabwe's state-run Herald newspaper.
It is illegal to publish unofficial election results in Zimbabwe. Police have warned they would take action against anyone trying to leak early results.
Zanu-PF and Mr Tsvangirai's Movement for Democratic Change (MDC) have shared an uneasy coalition government since 2009 under a deal brokered to end the deadly violence that erupted after a disputed presidential poll the previous year.
Speaking in the capital Harare on Friday, Mr Obasanjo said the elections were fair and free "from the campaigning point of view".
The former Nigerian president admitted that there were "incidents that could have been avoided", but he stressed that the 69 AU observers did not believe those irregularities could change the overall outcome of the poll.
At the same time, the AU mission expressed concern at the high number of voters turned away and those being assisted to vote - usually reserved for the illiterate or the infirm.
In a statement, it also noted that 8.7m ballot papers were printed - 35% more than the number of registered voters.
Shortly afterwards, monitors from the Southern African Development Community (SADC) - which had 562 observers - described the elections as "free and peaceful" but said it was too early to call them fair.
"In democracy we not only vote, not only campaign, but accept the hard facts, particularly the outcome," said SADC mission head Bernard Membe, according to the AFP news agency.
Mr Obasanjo's assessment sharply contrasted to that of the Zimbabwe Election Support Network (ZESN) - the largest group of domestic monitors with some 7,000 people on the ground across the country.
It said on Thursday that the elections were "seriously compromised", with as many as one million people unable to cast their ballots.
The ZESN said potential voters were much more likely to be turned away from polling stations in urban areas, where support for Mr Tsvangirai is strong, than in President Mugabe's rural strongholds.
The group also alleged significant irregularities before the poll. It said that 99.7% of rural voters were registered on the electoral roll in June compared with only 67.9% of urban voters.
But speaking to al-Jazeera, Mr Obasanjo questioned ZESN's conclusions, describing them as "not verifiable".
He said he was satisfied that the apparent anomalies between urban and rural voter registration had been explained by the registrar-general, who had the accurate figures for births and deaths.
Mr Obasanjo also said that Mr Tsvangirai's camp should have addressed concerns about the electoral roll before the vote - not after.
MDC member and Finance Minister Tendai Biti told the BBC that the assistance voting in rural areas was a "euphemism to say you have to vote for Zanu-PF under the guidance and watch of someone else".
"They [Zanu-PF] have stolen the election so much so that they are embarrassed at what they have done," Mr Biti added.
Still, Mr Obasanjo's assessment of the elections is a big boost for President Mugabe and a heavy blow for his opponents, the BBC's Andrew Harding in Johannesburg says.
It is unclear now how Mr Tsvangirai intends to fight on, our correspondent adds.
On Thursday, the prime minister said the elections were "null and void".
"Our conclusion is that this has been a huge farce. It's a sham election that does not reflect the will of the people."
Extra police units - some in riot gear - have been deployed in Harare.
Under the electoral law, if no presidential candidate gains 50% of the ballots, a run-off will be held on 11 September.