Following the appointment of Véronique Laury as Kingfisher CEO on 10 September, there are currently five female chief executives in the FTSE 100.
Egon Zehnder UK head of diversity Karoline Vinsrygg told HR magazine the company has "done the maths" on the target and sees it as achievable.
"We'd need about three female appointments per year, which isn't too far away from what we have now, with the current rate of attrition and appointments," she added. "This would only require an average of one-in-six CEO positions going to women."
Vinsrygg added that she wants the campaign to be a long-term focus and not to be talked about briefly and forgotten "in a few days".
"We want buy-in from all areas," she continued. "Business really needs to get behind this, and for aims like this to be met government support is also a huge help. We know 25% isn't parity but we think it's a target that would demonstrate real progress."
James Martin, Egon Zehnder's head of the London HR practice, pointed to research that suggests there is still "a considerable amount of systemic bias" in the selection process.
"A great deal of our focus in recent years has been on discovering more effective ways of assessing and developing talented executives, as well as working with our clients to help enhance their executives' skills in this important area," he said.