In what is likely to be seen as a major endorsement for paternity leave, Facebook Inc. CEO Mark Zuckerberg has announced he will take two months off when his daughter is born.

In a Facebook post Friday, Zuckerberg announced he would take time away from leading the company in the first months of the baby's life.

"This is a very personal decision, and I've decided to take two months of paternity leave when our daughter arrives," his post reads.

"Studies show that when working parents take time to be with their newborns, outcomes are better for the children and families."

His post was accompanied by a photo of a stroller he has chosen with his wife, Priscilla Chan.

Zuckerberg and Chan announced in July they are expecting a baby girl following three miscarriages, but did not give a due date.

Zuckerberg post

Zuckerberg's post shows preparations for the impending arrival of a baby girl. (Facebook)

Facebook offers U.S. employees up to four months of paid maternity or paternity leave, considered generous by U.S. standards.

While Silicon Valley firms have rushed to extend such benefits in an effort to retain talent, many workers do not take up the offer for fear of missing out on promotions or being cut out of the information loop at work.

Zuckerberg, 31, did not say who would be running the company, an omission stock investors seemed to frown on, pushing Facebook stock down by 0.6 per cent on the day.

It is unusual for high-level executives to take paternity leave.

When Yahoo CEO Marissa Mayer had her first child in 2012, she took just two weeks off, and when she announced she was pregnant with identical twin girls in September, she said her maternity leave would be "limited."