The Bears could lose by as much as 12 points to retain the Frank Hyde Shield, but the 14 point loss sees the trophy head to Henson Park this season.
Norths scored first through Mitch Buckett in the seventh minute of play, with Dylan Farrell's conversion taking the six-nil.
The Jets levelled the scores four minutes later when Kane Evans scored a try and Paul Rokolati converted, taking the score line to six-all.
Buckett scored his second in the 15th minute, followed by a 23rd minute try to Chris Centrone which took the score line to 16-6 in favour of North Sydney.
The Jets scored two tries through Ryley Jacks in the 31st minute and Nafe Seluini in the 35th minute to level the scores at 16-all, before Shaune Corrigan crossed for the red and blacks in the penultimate minute of the half to go into half time with a 20-16 lead for the Bears.
Newtown hit the lead in the 61st minute when Jacks scored his second and Rokolati converted, but the Bears wrestled the lead back four minutes later when Justin Hunt scored, taking the score line to 24-22 in favour of Norths.
From there it was all Newtown, with tries to Usaia O'Sullivan, Evans, and Saulala Houma securing the 38-24 win.
Newtown Jets 38 (Kane Evans 2, Ryley Jacks 2, Nafe Seluini, Usaia O'Sullivan, Saulala Houma tries; Paul Rokolati 5 goals)
North Sydney Bears 24 (Mitch Buckett 2, Chris Centrone, Shaune Corrigan, Justin Hunt tries; Dylan Farrell 2 goals)