Nuri al-Maliki on Wednesday said the names of the defence, interior and national security ministers would be finalised in the coming three days.
"All points of view of the political blocs have come together, and the name of the candidates will be presented on Saturday," he said.
The announcement is set for exactly one week after al-Maliki swore in 34 members of his government on May 20 - the country's first permanent, four-year government since the US invasion.
The government is formed of four major political blocs, though dominated by al-Maliki's own conservative Shia United Iraqi Alliance, and every cabinet post was subject to lengthy negotiations between the political parties.
Initially there was no agreement over who would run the defence and interior ministries responsible for security, and the posts were left open during the inauguration.
In the days since, security issues have been underlined by a rise in violence.
A bomb exploded on Wednesday close to a crowd of Iraqi workers gathered to seek day labouring jobs in a Shia district of Baghdad, wounding a number of people.
Police sources said the blast in al-Kadhimiya area, in the north of the capital, was the second such attack in the past few days directed at crowds of mainly Shia men looking for work.
Police said it did not appear as if the blast had caused any deaths.
It came a day after three bombs in Baghdad killed at least 21 people on Tuesday, attacks that underlined the security challenge facing Iraq's still incomplete government.