A Facebook post showing an all-male group of NSW elite paramedic recruits has sparked an internal investigation over whether the team has a gender diversity problem.

The photos, which depict 18 new Special Operations paramedics, attracted attention online last month when they showed the new team as being entirely male.

After issues were raised about the photos, commissioner and chief executive of NSW Ambulance Dominic Morgan told budget estimates on Thursday that he ordered an internal investigation into whether selection practices for the squad had become exclusionary, and if sexism was at play.

The director of Special Operations and NSW Ambulance's director of people and culture are now looking into whether there are gender diversity problems within the team.

"The organisation has taken immediate action with the two most senior people involved," Dr Morgan said.

He said in the past Special Operations officers also functioned as rescue paramedics.

"Historically, there have been high physical fitness standards," Dr Morgan said.

Some of the physical assessments include carrying 30kg of rescue equipment, and work is now being done to evaluate if this was giving men an unreasonable advantage.

The team is able to access patients in complex circumstances, including when a person has fallen down a cliff and paramedics need to abseil to retrieve them.

Greens MP Cate Faehrmann questioned whether the internal probe was sufficient, saying she was aware of female paramedics who had applied for the roles and been knocked back.

"Every single member of the Special Operations team is male," Ms Faehrmann said.

"It makes female paramedics feel devalued. It's been a demoralising force."

Dr Morgan said the first step would be to establish whether a diversity issue existed within NSW Ambulance, adding that significant work had been done to address diversity within the organisation.

He said the organisation has a 50-50 representation of female to male paramedics, compared with just a handful of women in the organisation three decades ago.

Dr Morgan said women now outnumbered men in the executive department.