There had been hopes that Nuri al-Maliki, the Iraqi prime minister, would swear in the two new ministers when the 275-member parliament convened for a closed session on Sunday.
Sectarian divisions between Iraq's many political parties have already delayed the nomination of ministers for months.
However, despite a deadline for their naming passing last week, no agreement was reached, politicians said.
"They will not be named today," Baha al-Araji, a Shia deputy said. "We hope [they will be] within three days."
On Saturday, Jalal Talabani, the Iraqi president, had said he would hold a meeting with leaders of Iraq's political blocs to speed up the process of naming both ministers, however he did not say when the meeting would be held.
Hassan al-Sunaid, a parliamentarian with the prime minister's Dawa party, said he thought a pair of former Iraqi army generals, one Sunni and one Shia, would be chosen, although this could not be confirmed.
Members of the government also argued over a demand by Shia and Kurdish coalitions to curb the power of Mahmoud al-Mashhadani, the Sunni Arab parliament speaker.
They argued he should consult both Shia and Kurd deputy speakers before making decisions.
Meanwhile, at least three people in central Baghdad died after two bombs went off in succession.
At least one person died in the first blast, in the Karrada neighbourhood, while two bystanders were killed by a second device which exploded as people had gathered at the scene of the first, police said.
North of Baghdad, a regional governor also survived a gun attack that killed one of his bodyguards, local sources said.