During his speech on Friday, Burnham promised to deliver “the most significant changes to our policies in 40 years.”
At the same time, he made five promises to the public, including working with other parties in a “distinctly Labour” direction and transferring power from Westminster to local authorities.
But despite Burnham’s promises to stop scoring points at Westminster, Badenoch told the BBC: “I will score as many points as possible if it means doing the right thing for the country.”
“What I’m not going to do is give Andy Burnham a blank check.”
“What the country needs now is someone who can make the tough decisions, who can stand up to Labor MPs who don’t want to do anything difficult. And that’s what worries me,” she added.
Badenoch stressed that she likes Burnham, whom she dated before, calling him a “nice guy” and a “people buddy.”
She explained: “This job is not a popularity contest. She makes life better for everyone outside of this building. And he didn’t say what he was going to do. This is all nonsense.”
In a direct criticism of Burnham’s first speech as Labor leader, Badenoch accused the former Manchester mayor of being “a man who was talking to the Labor Party and not to the country”.
“It was all about the Labor Party, this Labor Party, their factions, their issues. “I’m not sure he understands the country’s priorities and if he becomes prime minister without that, I think he will, to use his own words, advocate a rude awakening,” she told the BBC.
Burnham, who returned to Parliament a month ago in a by-election, emerged as the sole leadership candidate after he was backed earlier this week by 379 Labor MPs, as well as all 11 of the party’s unions.
But ahead of his first speech on Monday, the new prime minister remains tight-lipped about who will fill the top positions in his cabinet.