The backbencher added that Mr Corbyn should quit as leader if Labour is not the largest party in the Commons after the next general election.
The Birmingham Yardley MP, who is a critic of Mr Corbyn, said she “might” make a bid for the party’s top job if she believes she can make a difference when the time comes.
We’ll tell you what’s true. You can form your own view.
a day, more exclusives, analysis and extras.
Ms Phillips previously hinted at wanting to be prime minister in a Times interview in March, saying: “And why not? I think I’d be a good prime minister.”
Her latest comments come after shadow chancellor John McDonnell said on Friday that he and Mr Corbyn would stand down if Labour loses the next election – and that the next leader should be a woman.
Speaking at the Cheltenham Literature Festival about whether she would run for the top job, Ms Phillips said: “Might do, yes. The answer is I genuinely don’t know. I’d have to see how the land lay at that moment.
“What I don’t want to be is just a personality in politics. We have gone too far down that rabbit hole.
“If I stand it has to be not just because people trust me, people do trust me, it isn’t just because people feel connected with that.
“That’s not enough, it has to be about having a genuine plan for the future for our country.
“At that time, I would make that assessment about whether I was the best thing for the future of the country.”
Ms Phillips said it is “not impossible” for Labour to become the largest party at the next poll, but admitted that a majority is unlikely.
She said: “I don’t think anyone will win an election.
“It’s not impossible and anything could happen. I could see the numbers last time and a lot of people said to me: ‘See what happened last time’.
“What happened last time was that the Labour Party didn’t win the election.
“So, it could be the biggest party and even when I look at the polls, and I see the Tories are surging forward at the moment, I actually can’t see the numbers where they make up the seats that they’ll lose in Scotland.
“If it was proportional representation then the Tories would end up the biggest party, but our system is weird.”
Additional reporting by PA