Mr Mugabe’s government has declined to issue Mr Tsvangirai with a full passport, and due to visa issues he was unable to use his emergency travel document to go to a ministerial meeting in Mbabane, the Swazi capital.
"We can’t travel to Swaziland without our principal," said Tendai Biti, the chief negotiator of the Movement for Democratic Change, speaking in Johannesburg.
The MDC demanded an emergency summit of the regional Southern African Development Community (Sadc) after boycotting the talks with Mr Mugabe’s Zanu-PF party, due to be held in Swaziland.
Mr Biti described the passport issue as "a symptom of the real problem in Zimbabwe".
He added: "There’s no reality check on the part of Zanu-PF, there’s no readiness on the part of Zanu-PF to engage in a co-operative government with Morgan Tsvangirai and the MDC.
"It’s time that a full extraordinary summit of Sadc is reconvened not only to look at outstanding issues but to say to President Mugabe: ‘enough is enough’."
The stand-off leaves the country’s power-sharing process at its lowest ebb since an agreement between the parties was signed, amid huge optimism, five weeks ago. Since then they have failed to settle the allocation of ministries between them, and Mr Mugabe has unilaterally declared that all key posts, including home affairs, which includes control of the police, will go to his Zanu-PF organisation.
Thabo Mbeki, the former South African president who is mediating the talks, failed to resolve the impasse in several days of negotiations in Harare last week.
Mr Biti insisted that it was not a mistake to sign the agreement without first settling the question of ministries, even though he said there were significant differences between the text the leaders initialled and the final version signed at the ceremony.
Nonetheless he said that in the face of Zimbabwe’s humanitarian crisis – inflation is officially 231 million per cent and five million people will soon need food aid – the MDC would be the last people to walk away from the process.
But the reality is that while Mr Mugabe shows every sign of clinging to power, Sadc has never imposed meaningful pressure on him in the past and even if it were to do so, he is likely to resist it to the last.