Nine judges, led by Chief Justice Luke Malaba, are hearing the case brought by the opposition MDC Alliance over the results of July’s election which it says was rigged.
The party’s lawyer Thabani Mpofu told the court there had been a massive cover-up and doctoring of results and he wanted to see President Emmerson Mnangagwa’s victory overturned.
The governing party’s lawyer, Thembinkosi Magwaliba, and the electoral commission said the opposition had failed to produce any evidence of fraud.
The BBC’s Shingai Nyoka in the capital, Harare, says the Zimbabwean authorities are acutely aware of the simmering tensions the case has brought.
President Mnangagwa, who narrowly avoided a run-off election by taking 50.6% of the vote, has urged the court to throw out the opposition challenge