Labour’s Easington representative, Grahame Morris, and Blyth Valley’s Ronnie Campbell, were backing Andy Burnham in the Labour leadership race, but this week ditched him in favour of Jeremy Corbyn.
Newcastle Central MP Chi Onwurah, who is one of the last in the region to reveal her nomination, has also announced her support for Mr Corbyn.
The leadership race has so far seen Andy Burnham take the pole position with 53 nominations from MPs, with Yvette Cooper on 46, Liz Kendall on 37, Mary Creagh on seven, and Jeremy Corbyn on 13.
Mr Corbyn, 66, has a track record of rebellion against the Labour party, regularly defying the whip. In January he was among a number of MPs who wrote an open letter to Ed Miliband calling on the party to oppose further austerity.
Ronnie Campbell, who has represented Blyth Valley for Labour since 1987, said: “I’m making a point and Grahame is doing the same and the point is that there are still socialists.