President Mugabe's ruling Zanu-PF lost its parliamentary majority
Zimbabwe's electoral commission has ordered a recount of ballots in 23 constituencies in disputed elections held two weeks ago, local media says.
The recount would happen on Saturday, the state-owned Sunday Mail reported.
With tensions rising over unreleased presidential poll results, the information minister said the army would not be used against the people.
The opposition, which says it won the presidency, has accused the government of planning a campaign of intimidation.
The chairman of the Zimbabwe Electoral Commission, George Chiweshe, said the results from 22 districts had been disputed by the ruling Zanu-PF party, while the opposition Movement for Democratic Change (MDC) contested the count in one constituency.
The MDC says Morgan Tsvangirai won the presidential election outright
Correspondents say the recount involves enough seats to overturn the original results, which gave the MDC a narrow lead in the lower house of parliament.
The recount will be of all presidential, parliamentary, senate and council votes cast in the 29 March elections in the affected constituencies.
The MDC has made it clear that it will not accept results based on recounts.
"For us, that is accepting rigged results," MDC spokesman Nelson Chamisa told Reuters news agency.
"They had custody of the ballot boxes for two weeks and they must have stuffed them with their votes."
The opposition has accused President Robert Mugabe, who has been in power since independence in 1980, of beginning a campaign of violence ahead of a possible run-off vote.
"Mugabe has deployed the military in the provinces, in the districts. People are being beaten up," the MDC's Morgan Tsvangirai told the BBC on Friday.
But Information Minister Sikhoanyiso Ndlovu told the Sunday Mail that "the army will not fight against Zimbabweans because it is there to protect them".
"I believe everyone in the country is aware that there is no military junta. The soldiers are in the barracks where they belong because the country does not fully require their services in such a peaceful environment," he said.
The developments followed a call from southern African leaders for the still unpublished presidential poll results to be speedily announced.
After a summit in Zambia aimed at breaking the deadlock in Zimbabwe, Southern African Development Community (SADC) leaders also urged all parties to accept the election results and asked South African President Thabo Mbeki to continue his role as SADC's "facilitator on Zimbabwe".
Police have been on the streets in the capital Harare
Mr Mugabe declined an invitation to the summit of the 14-nation body, sending a delegation of ministers instead.
MDC Secretary-General Tendai Biti described the summit outcome as a "major improvement".
But he called on Mr Mbeki to show "more vigour, more openness and a complete abandonment of the policy of quiet diplomacy".
Mr Mbeki met Mr Mugabe in the Zimbabwean capital, Harare, before the summit, saying there was "no crisis" in the country and calling for patience in the wait for official results.
According to results released so far, Zanu-PF has lost its majority in the House of Assembly for the first time since independence in 1980, winning 97 seats against the MDC's 99 in the 210-seat chamber. A smaller MDC faction has 10 seats.
In the Senate, or upper house, Zanu-PF and the combined opposition have 30 seats each.
The opposition says its leader, Morgan Tsvangirai, won more than the 50% of the vote necessary to avoid a second round in the presidential contest, citing returns posted outside polling stations.
Under President Mugabe, a drawn-out economic collapse in Zimbabwe has seen hyper-inflation, massive unemployment and the departure of hundreds of thousands of people.