A new jobs site to help civil service employees find job-share partners and encourage flexible working among men has been launched.
At present, a fifth of civil servants work part-time, but 87% of those employees are women.
Treasury official Jonathan Lepper came up with the idea after he suffered a serious illness, which he said made him re-evaluate his priorities, particularly the amount of time he was spending with his children.
The job-share site is aimed at civil servants who want to work part-time, whether they have caring responsibilities, a disability or just want more time at home.
Helen Ghosh, head of the Department for the Environment, Food and Rural Affairs, who does not work on Friday afternoons, said she was proof that it is "possible to rise to the very top having worked in a variety of flexible ways".
She added that flexible working was beneficial to employers as such an arrangement could aid staff development because it depended so much on team work.
Cabinet secretary Gus O'Donnell said he wanted to encourage more men to take advantage of flexible working, and added one of his biggest regrets was taking a job as the prime minister's press secretary when his daughter was born, leaving all the parenting to his wife. "I wish we had had more flexible systems," he said.