The age people become eligible for free bus passes in Wales is to rise from 60 to the state pension age, under Welsh Government plans.
Ministers are concerned about the rising cost of the pass, with 880,000 people expected to be eligible by 2021.
Transport Minister Ken Skates confirmed the move, to be introduced gradually, will be included in a proposed new law.
The Older People’s Commissioner said she was concerned about the potential impact on the most vulnerable.
Details of when the changes will be introduced remain sketchy. The pass, introduced in 2002, entitles users to free bus travel.
The state pension age for men and women is 65, but will rise to 67 by 2028.
According to a recent consultation, pass-holders represent about 47% of bus journeys in Wales and there were about 730,000 passes in circulation at the end of 2018.
Age Cymru said people such as carers, those with disabilities or those from ethnic minorities may find it more difficult to continue working to a state pension age, and would be “less able to cope with a loss of an entitlement such as free bus travel”.