Theresa May refused to be interviewed on Woman's Hour, sending another member of her team in her place.
Critics said that the prime minister's refusal to do media appearances was "very serious" with less than a week of campaigning left.
Presenter Jenni Murray confirmed that Ms May had been invited to appear on the show, but had turned it down because of her "schedule". It is the latest appearance that Ms May has refused, after she declined to take part in the BBC's election debates and sent home secretary Amber Rudd instead.
Ms May had originally intended to send Amber Rudd to Woman's Hour, but Ms Rudd's father died recently and so was unable to appear. As such, the prime minister said education secretary Justine Greening instead.
Rumours of the refusal led to criticism from critics who claim that Ms May is avoiding media appearances. Labour-supporting columnist Owen Jones, for instance, sent a number of tweets in which he said that the cancelling of interviews is "rather serious".
Theresa May has rejected claims that her campaign is undergoing a "wobble" that began after intense criticism over her social care plans. The Conservatives' lead over Labour has narrowed in recent weeks, with some polls even suggesting that Ms May will fail to win an outright majority.
"Campaigns are all the same," she said. "You just work at them throughout the whole campaign."
Ms Greening's appearance comes after Jeremy Corbyn appeared on Woman's Hour and was unable to remember a figure from his manifesto, an appearance that led to its own negative reaction from critics.
