Four senior ministers in the Abbott government have been assigned secret-service style protection amid an angry backlash over the federal budget, while a fifth minister is also receiving personal protection over specific threats.

The unprecedented ramp-up in security measures has seen Treasurer Joe Hockey, Foreign Minister Julie Bishop, Education Minister Christopher Pyne and junior Defence minister Stuart Robert assigned Close Personal Protection officers from the Federal Police in the month since the budget.

Immigration Minister Scott Morrison has also been assigned CPP teams in recent months, with his controversial portfolio said to be the reason to ramp-up protection, not the budget.