"This is the occasion when it's either, they accept, or it's a break," Mugabe was quoted by the Sunday Mail as saying. "If they have any issues they deem outstanding, they can raise them after they come into the inclusive government."
But Tsvangirai's Movement for Democratic Change insisted Sunday that all outstanding issues be resolved before a unity government was formed - not after.
The political deadlock has prevented authorities from addressing a spiraling economic crisis, with the central bank last week introducing a new 100 trillion Zimbabwe dollar note to keep pace with dizzying price increases. Inflation is officially at 231 million percent - in reality much higher. The health, water and education systems have collapsed, and most major goods are in shortage.
More than 5 million Zimbabweans are likely to be dependent on food aid this year, and a cholera epidemic has killed more than 2,200 people and infected over 42,000.
Under the power-sharing accord, 84-year-old Mugabe would remain president, Tsvangirai would become prime minister and nearly all major Cabinet ministries would go to Mugabe's party.
But Tsvangirai has said he would not be "bulldozed" into joining a lopsided government, after winning the first round of presidential elections in March but pulling out of the runoff because of violence against his supporters.
On Sunday he reiterated demands that his party receive an equal share of Cabinet portfolios. In particular, he wants control of the Home Affairs Ministry in charge of police, who are accused of a wave of abductions of opposition supporters.
The opposition party also wants a say in how Zimbabwe's National Security Council is composed and run. And the party's executive committee demanded after a meeting Sunday that their imprisoned supporters be released.
The talks Monday also include the presidents of South Africa and Mozambique and regional mediator Thabo Mbeki.
But Mugabe indicated his patience was running out.
"We have gone past negotiations, and whatever concessions were there to be made have already been made," the Sunday Mail quoted him as saying.
Opposition party spokesman Nelson Chamisa said that if Mugabe was "arrogant" enough to terminate the talks "it would be for everyone to see that he is not sincere in resolving the country's problems."
In a separate development, a British photographer said Mugabe's wife punched him repeatedly in the face last week after he tried to take pictures of her near the luxury Shangri-La hotel in Hong Kong.
Richard Jones said Grace Mugabe, 43, ordered a bodyguard to hold him down and then attacked him herself Thursday. He said he was on a freelance assignment for London's The Sunday Times.
"She directed several punches into my face," Jones told The Associated Press on Sunday. "She was wearing diamond-encrusted rings, which caused a lot of lacerations."
Jones, 42, from Machen in South Wales, said he suffered at least 10 cuts to his face but did not need hospitalization.
Hong Kong police said they were investigating the alleged incident but have made no arrests. They did not give the identity of the alleged attacker.
The Sunday Times said Zimbabwe's first lady has since left Hong Kong, where she was visiting her daughter Bona, a student there.
