"This step is a little late, but we welcome it," a statement from Prime Minister Haidar al-Abadi's office said.
The Baghdad government had requested members of the US-led international coalition battling Islamic State group (IS) jihadists to help train and arm its forces, the statement said.
"The coalition agreed on that and four to five Iraqi training camps were selected, and building on that, they have now begun sending the trainers," it said.
Multiple Iraqi divisions collapsed in the northern province of Nineveh in the early days of the jihadist offensive, leaving major units that need to be reconstituted.
Experts say Iraqi security forces suffer from serious shortcomings in training and logistics, hampering their performance in the conflict.