"But given I live in the electorate, I know many of the people, it is at least something I should give consideration to."
There has been ongoing speculation King would step aside to give Little an electorate after his two failed tilts to win New Plymouth. He made it back into Parliament by a narrow margin after 2014.
King, 69, denied her decision was part of any arrangement with Little, saying she simply believed it was time for another generation to take on the electorate.
She did not know if Little wanted to stand there and had made her own decision to step aside.
"Nobody has ever asked me to leave. In fact, the opposite. I'm asked nearly every day 'are you going to stand'."
Little said in National the leader and finance minister were also both now list MPs "and that reflects on a modern MMP environment".
Labour nominations for Rongotai selection close in early February.
Bill English is the first list MP to become prime minister but no elected PM has been a list MP so far. English had represented the Southland electorate for 24 years before deciding to stand on the list only in 2014.
King said she was sad but after 24 years it was time for someone else to take over.
"I'm in the 60s generation, we need somebody in the 40s or round that age. You need somebody that can take on the seat and do it for 20-odd years.
"So it's an end of an era for me. It's been my life for a long time and I feel a bit tearful, but you have to make a decision and I've thought about this and thought about it for a long time.
"It's an absolutely wonderful seat. It's a Wellington one, it's got all the different communities from refugees through to professional people, the film industry, you name it."
King kept her roles as deputy leader and health spokeswoman in Little's reshuffle yesterday.
