It is not known yet whether or not Mugabe has retained the presidency.
However, the MDC began announcing its own tally a day earlier and claimed on Monday that its results, based on counts posted at polling stations in 128 of the country's 210 parliamentary districts, showed it was leading presidential elections with 60 per cent of the votes compared to 30 pe rcent for Mugabe.
Utoile Silaigwana, the deputy chief elections officer, declared the results in a nationwide radio and television broadcasts on Monday.
The election commission had said the delay was due to presidential and parliamentary elections being held at the same time, but the piecemeal announcement has left observers questioning the transparency of the process.
Kamahl Santamaria, reporting from Harare, the capital, said there was a lot of frustration considering that no word was heard from the ZEC (Zimbabwe Electoral Commission) for quite a while.
Al Jazeera's Haru Mutasa, reporting the town of Bulawayo, said that speculation is rife due to the delay in the announcmeent of results.
She said: "This is an opposition stronghold, and they are hoping to win the presidential elections."
Mutasa also said that if they lose the lections, they will blame it on rigging."
"Many here believe the reason why results are taking so long is because government officials are trying to rig the elections."
Some election observers have said that initial results were known by 11pm (2100 GMT) on Saturday night, just four hours after polls closed.
In previous elections, partial results have been announced within hours of voting ending.
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.
The opposition has already claimed victory in the vote that posed the biggest threat ever to Mugabe's 28-year rule.
Riot police patrolled Harare on Monday as the first results came in.
Before the polls, police said they would crush any premature celebrations but they were striking a softer line on Monday after a weekend of impromptu victory parties by MDC supporters.
"Police are very much still on high alert and appeal to those wanting to celebrate to do so with respect for other people," Wayne Bvudzijena, national police spokesman, said.
"It's human to celebrate but they should not provoke, intimidate or insult others."