Envoys from Iraq's neighbours began arriving in Syria on Saturday. But Iraq's interim foreign minister, Hoshyar Zebari, has said he will not take part in the Damascus meeting because he did not receive a proper invitation.
His move means diplomatic manoeuvring to satisfy both the host Syria, which was reluctant to see occupied Iraq participate, and to placate the US-installed government in Baghdad, has failed.
"The way the invitation has been extended was not in keeping with Iraq's dignity," Zebari told a Baghdad press conference on Saturday.
Syria had called the meeting of seven regional foreign ministers to discuss the impact of violence in Iraq on the region's stability.
But it had initially failed to invite Zebari because of its continued misgivings about the legitimacy of his US-installed administration.
Following a boycott threat by US allies Jordan, Kuwait and Saudi Arabia, Syria agreed to an 11th hour compromise whereby Zebari would take part in the formal talks but not in a brief informal preliminary meeting.
"In the absence of a frank and clear invitation from the Syrian government for Iraq to participate in the Damascus meeting, it is impossible to take part"
interim Iraqi foreign minister
The move was welcomed by Jordan - but it was clearly not enough for the Iraqi minister.
"In the absence of a frank and clear invitation from the Syrian government for Iraq to participate in the Damascus meeting, it is impossible to take part," Zebari said.
"We do not accept any recommendations or decisions that come out of this meeting without Iraq's participation," he added.
Zebari had been due to join the ministers from Egypt, Iran, Jordan, Kuwait, Saudi Arabia, Syria and Turkey for the main gathering.
Earlier, Jordan had welcomed the decision to allow Zebari to take part.
"We believe Iraq ought to be represented at any meeting dealing with the country," Foreign Minister Marwan Muasher told AFP before his departure from Amman for the meeting.
"We believe Iraq ought to be represented at any meeting dealing with the country"
foreign minister, Jordan
"We are in favour of any cooperation with the interim Governing Council that might lead to a rapprochement between Arab states and Iraq, and help put an end to the occupation of the country and improve its internal situation."
Muashar said it would have been perverse to have denied Zebari a seat in Saturday's talks given that Arab ministers had already admitted him to an Arab League meeting in Cairo in September.