"The values are really clear, it talks about loyalty to the country and the Crown. It talks about citizenship for all people and equal opportunity.
It had been speculated that Ngaro would try for the Botany seat held by now independent MP Jami-Lee Ross.
Ross said he was not surprised Ngaro chose the safe option of a list seat.
National needed potential coalition partners and Ross said it was alarming that Bridges had not ruled out working with the recently formed Coalition New Zealand party.
Coalition New Zealand leader Hannah Tamaki said "Good on Alfred for letting his colleagues and party know where his loyalties are and choosing to remain with the National Party.
"As Alfred said, he's under no illusion about how hard this will be. He's right, it takes courage and resilience to stand and live by your convictions."
Tamaki last week raised the possibility of working with Ngaro after she and her husband, Destiny Church leader Brain Tamaki, announced they would set up Coalition New Zealand.
New Conservatives deputy leader Elliot Ikilei wished Ngaro luck but said the party would press on with its pursuit of the Botany seat.