Scott Morrison has joked that his fitness is not what it once was.

The Prime Minister was seen struggling to walk uphill during a 10km hike with a group of Aboriginal people in the Blue Mountains, west of Sydney on Saturday.

'I don't know if I like going up the hill or down the hill but at our age you feel both,' the prime minister told 7News reporter Tim Lester.

Scott Morrison was seen struggling walking uphill during a 10km walk with a group of Aboriginal people in the Blue Mountains

Run by the Clontarf Foundation, which assists about 8,000 Indigenous people with school and finding a job, Mr Morrison (second from right) promised to make the bushwalk an annual event

At one point Mr Morrison grabbed the shoulder of a man in front of him as he struggled to walk uphill.

The walk is run by the Clontarf Foundation, which assists about 8,000 Indigenous people with school and finding a job.

Mr Morrison promised to make the bushwalk an annual event.

'Young men who in one generation have completely changed the course of their family's lives...that blows you away,' Mr Morrison told the group.

The young men were excited to have Mr Morrison join them on the walk and said they could now call him their friend.

At the end of the walk, the group gathered to sing I Am Australian by The Seekers, with Mr Morrison strumming on a ukulele.