National's Jami-Lee Ross, Jonathan Young, Todd Muller, Chris Bishop and Brett Hudson are the latest to say they will back English.
Muller and Bishop are among a group of back bench MPs who pushed for a contested leadership race.
"New Zealanders are looking for strong leadership, continuity and stability," Muller said in a statement.
"The world is in a heightened state of flux and Bill has the experience and wise judgement to guide New Zealand successfully through these times."
Muller said he would support Simon Bridges for Deputy Prime Minister. Paula Bennett is also seeking the deputy role.
Ross, who is National's junior whip, chose English despite having a close relationship with Collins.
"I am a friend of Judith Collins," he said. "I am also a friend of Jonathan Coleman. I respect them both as Members of Parliament but I believe that Bill English delivers the stability that New Zealanders deserve."
Ross said he supported a contest for the deputy role. He said the position created an opportunity to consider generational change.
Young, National's MP for New Plymouth, said English was strong on policy, good at managing people and experienced with the media.
"I think he will be the better front-person for the party and as Prime Minister."
He said while English represented continuity he agreed with calls for some regeneration in the party ranks. "I think to build resilience in the leadership of the party there has to be both."
"I think the cream rises to the top. When you think of the last couple of years , we as a Government have by and large been high performing. So it's quite difficult to change a winning team.
He said he had decided to back English fairly early on.
"But because I hold the other candidates in high regard as well I have to give them the benefit of consideration."
