Iraqi security officials had warning of the bombings that killed 112 people in Baghdad last week but bureacracy and blunders tripped up efforts to stop them, according to its interior ministry.
The country's defence, interior and national security ministers were summoned to parliament to answer for the blasts that ripped through the capital.
It was the third major recent attack targeting government facilities, Reuters reports.
Interior minister Jawad al-Bolani says a misunderstanding of information, incorrect assessments, conspiracy and blackmail, are among the reasons the attacks were not foiled.
Iraqis have frequently criticised security forces for security breaches, and security officials near blast sites have regularly been rounded up for questioning after major attacks.