It is the first time Harriers have won their opening two league games since overcoming Mansfield Town and Darlington in the then Nationwide League Division Three in 2003.
Freemantle, Austin and Hemmings confidently sealed the points by scoring during a lethal second half display by high-flying Harriers.
Kidderminster made one change from the starting line-up when they launched their campaign seven days earlier with an impressive 2-1 win over title favourites York City at their new LNER Community Stadium.
Newcomer Geraldo Bajrami, the 21 year old former Albania Under 21 international and Birmingham City defender, came in for his debut in place of unwell Keith Lowe.
Harriers, playing their first home league fixture since drawing 2-2 with York on January 5, looked threatening in the first minute when Hemmings set up the opportunity for Omari Sterling to cut inside and fire in a shot across the face of goal.
Blyth, fresh from their 2-0 home opening day victory over Alfreton Town, responded with a promising raid which resulted in a seventh minute corner which proved fruitless.
Harriers were soon back up field and put the visitors rear-guard under pressure with a move which ended when Nathan Cameron shot straight at goalkeeper Alex Mitchell, who was then called on to fist away a powerful long range drive by Hemmings.
Austin also tried his luck from range shortly afterwards, but his effort was safely dealt with just under the bar by Mitchell who minutes later saved another effort from the same player.
Battling Blyth worried the hosts in the closing stages of the first half when a shot from Robbie Dale was pushed over the bar by goalkeeper Luke Simpson for an unproductive corner.
The visitors gave Kidderminster an anxious moment in the opening stages of the second period when a shot from Connor Thomson was scrambled away with difficulty by Simpson.
Harriers, however, broke the deadlock in the 52nd minute when a delightful reverse pass by Austin enabled Freemantle to blast an unstoppable shot past helpless Mitchell.
Shortly afterwards Bajrami had a header drop wide while another headed effort, this time by Hemmings, suffered a similar fate,
Kidderminster increased their lead in the 66th minute when Freemantle set up the chance for Austin to sweep the ball into the net.
It was 3-0 on 74 minutes when Hemmings wrapped up the scoring by running through the visitors defence before firing past Mitchell.
Kidderminster: Simpson; Foulkes, Cameron, Bajrami, Richards; Carrington, Martin; Hemmings (Lissimore, 90), Austin (White, 81), Sterling; Freemantle (Bell, 75). Subs not used; Emery, Penny.
Blyth: Mitchell; Byrne, Buddle, Lees, Liddle; Hickey (McKeown, 72), O’Donnell, Deverdics, Dale; Thompson (Reid, 57), Maguire. Subs not used: Evans, Watson, Painter.
Referee: David McNamara.
Attendance: 1,462 (47 away fans)