The Crisis Coalition, an alliance of Zimbabwean pro-democracy and rights groups in the Mozambique capital, said a summit communique was being prepared that would urge Mugabe to ask his nation's highest court to rescind a ruling ordering him to hold elections by July 31.
Mugabe will be asked to seek at least a two-week extension of the ruling and hold polls not before Aug. 14, the group said.
The official communique has not yet been formally released. No confirmation was immediately available from the secretariat of southern Africa's political and economic bloc, known as Southern Africa Development Community, or SADC.
No comment was given by Mugabe or his delegation.
MacDonald Lewanika, the Crisis Coalition director, said in a Twitter feed from the Maputo convention center that regional leaders agreed the election "is not time-driven but process driven" and more time was needed finalize preparations and voting reforms.
Zimbabwe Prime Minister Morgan Tsvangirai said on Friday that Mugabe's unilateral proclamation of the July 31 election date breached terms of the power sharing agreement forged by regional leaders after the last violent and disputed elections in 2008. That agreement required the coalition partners to agree on policy decisions and the holding of elections, he said.
Tsvangirai, in a shaky coalition with Mugabe, said democratic reforms also demanded in a new constitution and by mediators ensuring free and fair polls cannot be completed by July.
Polls after Aug. 14 would clash with one of the world's largest tourism gatherings, the United Nations World Travel Organization summit, that Zimbabwe is set to host on Aug. 24.
South Africa President Jacob Zuma, the chief regional mediator on Zimbabwe, started closed-door talks with Mugabe, Tsvangirai and other regional leaders earlier Saturday, officials said.
Zuma said in a statement the leaders were to consider "a roadmap" to elections in Zimbabwe. But a top Mugabe party official told South African state radio Saturday the summit will only seek financial help from the region to fund polls in July.
The Crisis Coalition said at the beginning of the talks that early elections risked not being recognized regionally or by Zimbabweans themselves unless reforms are in place and political violence and intimidation are brought to an end.
"Conditions are not ripe for free and fair elections. The security situation is not good ...we want SADC to ensure that violence is stopped and the media is free to report without intimidation," Lewanika told reporters.
A new constitution, overwhelmingly accepted in a referendum in March, has demanded reforms to sweeping media and security laws along with reforms within Mugabe's loyalist police and military blamed for state orchestrated violence in previous polls.
None of those reforms have been completed, Tsvangirai's party says.
Mugabe's party insists he was abiding by a ruling of the Constitutional Court, the nation's highest court, ordering him to hold presidential and parliamentary elections by the end of July, linked to the automatic dissolution of the Harare parliament on June 29, the end of its current five year term.
Independent lawyers' groups say that ruling does not follow provisions in the new constitution and can only be rescinded by the same court on an application from Mugabe.
Continuing amendments to electoral laws called for in the constitution and by regional leaders were effectively blocked by Mugabe's announcement of the poll date on Thursday, said Veritas, a legal research group.
Mozambique President Armando Guebuza, current chair of the regional grouping, said earlier Saturday that Zuma was scheduled to have presented a report to the one-day summit on Zimbabwe's readiness for elections.