Hamza Khamis, an explosives expert, said the engineering unit had secured the road linking the city centre to Tikrit University.
"After the liberation of Tikrit from ISIS militants, the explosives experts of the Engineering Unit affiliated to the Federal Police were able to dismantle more than 40 improvised explosive devices," he said.
Prime Minister Haider al-Abadi said the engineering units still need more time to clear Tikrit of booby traps.
The government declared victory over the ISIS group in Tikrit on Wednesday, and it warned the militants holding other Iraqi provinces that they would be the next to fall.
Recapturing Tikrit is seen as crucial to helping Iraqi forces in any future operation to retake Mosul.