Many expect Robert Mugabe, the president, who has ruled since independence from Britain in 1980, to hang on to power.
Despite calls from foreign governments, there was still no official word on the presidential contest between Mugabe, aged 84, and Morgan Tsvangirai, who heads the MDC. A third candidate, Simba Makoni, a former finance minister, is also in the race.
Based on its own calculations, the MDC is confident that it has won both the presidential and parliamentary contests.
However, a coalition of NGOs which deployed 8,000 local election observers has projected Tsvangirai will fall just short of the votes needed to beat Mugabe.
According to the Zimbabwe Election Support Network (ZESN), Tsvangirai won 49.4 per cent of the votes against 41.8 per cent for Mugabe, a result which necessitates a second round run-off later this month.
Tsvangirai has made no public appearance since voting day on Saturday when he accused the authorities of widespread rigging. He is expected to hold a news conference on Tuesday.
Riot police had been deployed on the streets of the capital, Harare, but by Tuesday the police presence appeared to be at normal levels.
The electoral commission says the delay is due to presidential and parliamentary elections being held at the same time and there being 60 constituencies more than in the last elections in 2005.
But the piecemeal announcement has left observers questioning the transparency of the process.
In previous elections, partial results had been announced within hours of the close of voting.
Notable early results included defeat for Patrick Chinamasa, Mugabe's outgoing justice minister, in the rural eastern constituency of Makoni central.
The MDC also won the first seat to be declared, the newly formed constituency of Chegutu West, to the west of Harare.
Al Jazeera's correspondents in Harare and the opposition stronghold of Bulawayo said there was a great deal of frustration because little had been heard from the ZEC fuelling speculation.
|Zanu-PF supporters celebrate in |
Mbere township in Harare [AFP]
Ebrahim Fakir, a senior researcher at the Centre for Policy Studies in Johannesburg, told Al Jazeera that the delay could be considered a win in the propaganda war for the opposition.
He also said it was against Zimbabwean law to declare an electoral victory before all results were released and the opposition was being "disingenuous", and the claim of victory was "rhetorical".
"We have also witnessed the lack of independent analysis and assessment of this election, and the lack of citizenry access to the political and democratic process in this country," Fakir said.
Riot police patrolled Harare on Monday as the first results came in.
Before the elections, police said they would crush any premature celebrations but they were taking a softer line on Monday after a weekend of impromptu victory parties by MDC supporters.
Wayne Bvudzijena, a national police spokesman, said: "Police are very much still on high alert and appeal to those wanting to celebrate to do so with respect for other people.
"It's human to celebrate, but they should not provoke, intimidate or insult others."