This was despite a strong defensive performance for the Harriers for the majority of the first half.
Two goals from Jack Lester, one from the penalty spot and strikes from David Johnson and Riccardo Scimeca made it 4-0.
Forest wanted to make light work of this fixture and nearly took the lead on the seventh minute, but for the crossbar denying Scimeca from his free-kick 22 yards out.
Minutes later Scimeca was in the thick of the action linking up with Lester before his shot was saved comfortably saved by Stuart Brock.
Kidderminster failed to get any sort of control, they had only one shot on target throughout.
Forest opened the scoring midway through the first half when German Eugen Bopp supplied a cross to the head of Lester who was loitering at the near post.
The lead was doubled for the Reds in the dying minutes of the first half when top scorer Johnson crossed for Scimeca to equal his tally in the goalscoring stakes with a volley leaving the Kidderminster keeper helpless.
In the opening minutes of the second half the goal provider became the goal scorer when young Craig Westcarr chipped to the head of Johnson, three yards out Johnson couldn't fail to score.
In the 71st minute Kidderminster Sean Parish brought down Chris Doig and a penalty was awarded. Lester stepped up to secure Forest's place in the second round with a fourth goal