An official from the ministry said on Thursday that police opened fire on two booby-trapped cars to prevent them from approaching the entrance, but the gunfire blew the cars up.
The Iraqi army and police then sealed the roads leading to the ministry to prevent another attack.
The wounded were taken to the nearby al-Kindi hospital for treatment.
In a separate incident in Ramadi, west of Baghdad, a US armoured vehicle was targeted by an explosive device after clashes erupted between anti-US fighters and American soldiers.
According to reports, extensive damage was done to property but no one was killed.
Much of Falluja was reduced to
rubble after the US attack
Meanwhile, a reconstruction conference in the devastated city of Falluja has called for an international committee to investigate the use of illegal weapons by US forces in their offensive against the town last November.
Falluja residents have alleged that US forces used chemical weapons during the offensive - a charge the Americans deny.
Delegates to the conference also called for the freeing of detainees and an end to the hunting of individuals and families.
They added that the US should fully compensate Falluja residents who suffered material loss during the attack and increase previous estimates of their losses.