European Union observers have listed several problems in Zimbabwe's presidential and parliamentary election, including voter intimidation and mistrust in the electoral commission.
Their assessment on Wednesday came as the main opposition leader accused the ruling party of trying to rig the result.
The observers also questioned delays in releasing the results of the presidential contest in Zimbabwe's first election since Robert Mugabe was forced to resign following a de facto coup in November after nearly 40 years in power.
Zimbabweans have been checking vote results posted outside polling stations in the capital Bulawayo. Source: AAP
The EU's assessment is critical in determining whether Zimbabwe can shed its pariah status as it could help attract investors and trigger an economic revival.
Mugabe's successor Emmerson Mnangagwa of the ruling ZANU-PF and Nelson Chamisa of the opposition Movement for Democratic Change were the main contenders in Monday's election.
The EU's Chief Observer, Elmar Brok, said he did not yet know if the shortcomings would have a material effect on the outcome of the vote, and he criticised the Zimbabwe Electoral Commission (ZEC) for being at times "one-sided".
The EU did not understand why the release of the presidential result was taking so long, he said.
"The longer it lasts that the results of the presidential election is not known, the more lack of credibility it provides," Brok said.
"The presidential results were counted first in the polling stations, therefore, I have still to learn why it will be published last."
With three seats yet to be declared, ZANU-PF had 144 seats compared to 61 for the MDC, meaning the ruling party achieved a two-thirds majority which would allow it to change the constitution at will.
Opposition leader Chamisa accused the ZANU-PF of trying to steal the election. He accused the commission of releasing the parliamentary results first to prepare Zimbabweans for a Mnangagwa victory.
"The strategy is meant to prepare Zimbabwe mentally to accept fake presidential results ... We won the popular vote (and) will defend it," Chamisa said on Twitter.
A crowd of about 100 MDC supporters gathered outside a Harare hotel where election results were being announced but police blocked the entrance to the building, a Reuters witness said.
"You can't rig our election...this is a military government", the crowd shouted. The situation was under control as police secured the area.
MDC Alliance supporters protest the vote count outside the Rainbow Towers in Harare. Source: AAP
African observer groups said the vote was peaceful, orderly and largely in line with the law but they raised concerns about bias of state media and the commission.
Zimbabwe was once one of Africa's most promising economies but under Mugabe's rule became tainted by corruption, mismanagement and diplomatic isolation. Its population of 13 million is struggling amid shortages of foreign currency, unemployment above 80 per cent and lack of foreign investment.
Chamisa's MDC won in most urban centres, where it enjoys majority support.
On Tuesday former MDC finance minister Tendai Biti and ZESN, the main domestic election monitor, said one in five polling stations - more than 2000 in all - had not physically posted tallies on their doors, as required by law.
That omission gave room for the electoral commission to manipulate the results in favour of the ZANU-PF party, Biti said.
On Wednesday, the EU addressed the same issue.
"It is imperative that the results process is credible and transparent, with a full breakdown by polling station so that confidence in the outcome can be assured," Brok said.
