Middle East special envoy Afonso Celso de Ouro Preto will travel to Amman to take up the case of Joao Jose Vasconcelos, Brazilian Foreign Minister Celso Amorim said on Monday.
Vasconcelos, 55, was working in Baiji for the Brazilian construction company Constructora Norberto Odebrecht SA, when he was seized last week by an Islamist group.
Aljazeera aired a videotape by a group claiming to be holding the Brazilian. Although the tape did not show the engineer it included his identification card, listing his name as Joao Jose Vasconcelos, 55.
The captors said the ambush was carried out as a joint attack between the Mujahidin Brigades and the Army of Ansar al-Sunna, but included no threats or demands.
Vasconcelos' family on Sunday expressed the hope that the captors would show mercy, noting that Brazil opposed the Iraq war.
After the capture, Brazil advised all its citizens to stay out of Iraq.