Concessionary tickets for public transport cost councils in Merseyside more than £50 million last year, figures show.
Councils across England say government funding for concessionary travel does not stretch far enough, forcing them to make up the shortfall to the tune of hundreds of millions of pounds.
Older and disabled people in England are entitled by law to free bus travel during off-peak times under the English National Concessionary Travel Scheme.
The scheme is funded via a government grant to local authorities, which are responsible for administering passes and reimbursing bus companies.
Department for Transport figures show the Liverpool City Region Combined Authority spent an estimated £53.3 million on concessionary travel during 2018-19.
It included expenditure on the statutory offering for elderly and disabled people, as well as any extra provision the council chooses to offer, such as extending free travel to peak times or discounts for students.
Across England, councils spent £1.1 billion on concessionary travel over the year, 79% of it on the ENCTS.
In May, the House of Commons Transport Committee warned that bus services were being put at risk by inadequate funding, after hearing evidence that councils were forking out up to £650 million a year to keep the ENCTS running.
The Local Government Association says it wants to see the scheme fully-funded, so councils can spend more money on concessions for other groups, or on subsidies for less popular bus routes that are at risk of being discontinued.
It said: "The number of bus journeys is at its lowest level in over a decade shows that more needs to be done to improve local services.
“Councils want to work with the Government to protect local bus services, which can be a lifeline for our most vulnerable residents, whether that is to go shopping, collect medication, attend doctor appointments or socialise with friends.
"It is vital the Government properly funds [the ENCTS] so councils can protect bus routes and reinvest in local networks."
In Merseyside, 344,876 people had a bus pass under the government scheme in 2018-19 – 86% of them elderly.
Together they made 35 million journeys during the year.
Youth concessions are also available, but these are offered by bus operators directly and not the council.
Charity Age UK says concessionary travel for older or disabled people has wider economic benefits, helping people be active in their communities and reducing loneliness.
Director Caroline Abrahams said: "The free bus pass is a real lifeline for many older and disabled people who would otherwise find themselves stranded at home and unable to afford to go out.
"Older people who are able to get out and about and stay engaged with their communities have a better chance of retaining their health and independence for longer."
A Department for Transport spokeswoman said: “This Government has committed to expanding better bus services, providing local authorities with funding to support £1 billion of spending on the free bus pass scheme, helping older and disabled people."