The U.S. Air Force plans to triple maternity leave for female airmen, the service's top civilian has announced.

The change would expand the leave from six weeks to 18 weeks and was inspired by a similar move by the Navy, Air Force Secretary Deborah Lee James said on Tuesday during a video town hall filmed at Fort Meade, Maryland.

"I believe in what the Navy did, I think it was the right thing to do, and we're going to do the same thing," she said.

The Navy's recently updated maternity leave policy allows new birth mothers to take 18 weeks as uncharged leave over the course of the first year after a baby's birth. The policy does not apply to fathers or adoptive parents. James did not specify whether the Air Force's policy would mirror those rules.

James said the expanded maternity policy may be announced as a goal for all of the military services as part of the second phase of Defense Secretary Ashton Carter's Force of the Future personnel plan. However, if it is not, James said, she is prepared to put it in place herself.

"It's a question of whether we do it under Force of the Future, or we wait and do it separately," she said. "But for now I want to wait and see what our Secretary of Defense does over the next month or so, so stay-tuned, but I'm here to tell you it's coming."

The complete town hall is available for viewing here. The maternity leave question-and-answer segment starts at about the 55-minute mark.

News of the expansion was met with enthusiasm from new moms on the Breastfeeding in Combat Boots Facebook support group page. Some, however, worried the policy would hurt mission readiness.

"As a mom I can see the benefit, but at the same time, I am an Air Force member and 18 weeks can greatly impact mission readiness in some duty sections," Angela Whitney Gookin wrote. "I know there is going to be a lot of backlash from this comment, but the military is not the same as the civilian sector, and trying to bring us in line without civilian counterparts, I believe, will have a negative effect."

--Amy Bushatz can be reached at amy.bushatz@military.com. Follow her on Twitter at @amybushatz.