"We are calling on the public to speak against ZEC [the Zimbabwe Electoral Commission] for failing to release the results," Thokhozani Khupe, the MDC's vice-president, said.
"We have called for a mass stay-in, starting tomorrow, until the results are released."
The police pledged to deal severely with any unrest during the called-for strike, announcing extra officers and soldiers were being deployed across the country.
"As everyone is aware, the past stay-aways have been characterised by random destruction of property and threats to life," said Wayne Bvudzijena, the police spokesman.
"Those who breach the peace will be dealt with severely and firmly."
As tensions increased over the delayed election results, Khupe said an MDC member was stabbed to death by supporters of the ruling Zanu-PF party, headed by Robert Mugabe, the president.
"We are sad to inform you that we have lost one of our members ... who passed away on Saturday after being stabbed by Zanu-PF supporters at his homestead," she said.
A police spokesman confirmed the death, but said it did not initially appear to be politically motivated.
The MDC claims that Morgan Tsvangirai, its leader, was the outright winner of the poll held on March 29, and that Mugabe is holding back the results as a result.
They say Mugabe is preparing a violent response to his biggest electoral setback - his party also lost control of parliament in a vote held the same day.
But the ZEC says it is simply still verifying the votes.
The ZEC has ordered a recount of 23 constituencies, a move likely to delay results even further.
The Zanu-PF party says that neither Tsvangirai nor Mugabe won an absolute majority in the presidential vote and a run-off will be necessary.
"Another delaying tactic"
The MDC had hoped that the court would force the election commission to release the results.
Andrew Makoni, an MDC lawyer, said: "It's a very sad day in Zimbabwe.''
|The police have pledged to deal severely with|
any unrest during the called-for strike [AFP]
"[The court] has given the Zimbabwe Electoral Commission a blank cheque. We don't know when the ZEC will be ready with results. We don't know what specific time would be reasonable in the eyes of the court."
Supa Mandiwanzera, Al Jazeera's correspondent in Zimbabwe, reporting from the capital, Harare, said the MDC strongly believed it had won the elections and saw the court decision as "another delaying tactic".
He said the MDC's subsequent call for a strike could "make or break" the party.
"If the stay-away is successful, then it will show the anger that the majority of Zimbabweans have, but if it is unsuccessful, it could also show that the MDC doesn't have any sway in terms of getting people on to the streets regarding this matter," he said.
Outside of Zimbabwe, international pressure for publication of the results has mounted.
At a summit in Lusaka, Zambia's capital, during the weekend, southern African leaders said the election result should be released "expeditiously".