Concerns for five bushwalkers after landslip at Wentworth Falls, Blue Mountains

A fifth member of the group was being helped out by emergency services.

The rescue operation was undertaken at Wentworth Falls near Wentworth Pass in the Blue Mountains on Monday afternoon.

NSW Ambulance Acting Chief Superintendent Stewart Clarke said it is "absolutely heartbreaking for all involved and a truly tragic ending to what I'm sure was meant to be a pleasant day out".

"It is terribly sad to have lost two lives here today and my heart goes out to the families and the survivors of this horrific ordeal who have witnessed what is certainly a traumatic event," he said.

"This was a really complex and delicate rescue operation for our crews who were working to access patients in rugged bushland and were navigating unstable ground."

Seven paramedic road crews including special operations paramedics and two rescue helicopters with a critical care doctor and a critical care paramedic on board were dispatched to the scene shortly after 1.40pm. On arrival, paramedics found five people: two with critical injuries, one was uninjured and two died at the scene.

The fifth member of the walking party - a teenager - was making her way out from the incident, assisted on the journey by emergency services.

A NSW Police media spokeswoman said emergency services were called to Wentworth Pass, Wentworth Falls about 1.40pm Monday "due to concerns for the welfare of five bushwalkers following a landslip near the pass".

A Blue Mountains Gazette reporter at the scene said there were about 50 emergency services vehicles there, including from the NSW Ambulance, Police Rescue, Fire and Rescue NSW, Police and National Parks and Wildlife staff.

The rescue is taking place in the area of the popular Wentworth Pass Loop walking track, a 5km walk described as challenging.

State Emergency Services volunteers have arrived on the scene and join National Parks climbers and Police Rescue specialists who have been taken into a briefing.

- with AAP