Southampton City Council has proposed scrapping subsidies for the X12 and W1 bus services, and admitted it could lead to "increased social isolation".
The plan is part of a public consultation on how the council can make £39m worth of budget cuts.
Age UK Southampton also said the move could hit the elderly.
Phil Williams, the charity's health and wellbeing officer, said: "We recognise how much pressure the council is under to further reduce its budget. I am sure they are carefully considering the proposal.
"Any removal of bus subsidies may have an adverse effect on elderly people to get out and socialise. The bus services are extremely highly valued by the people we work with."
A report in to the plans, which would see support reduced from £218,000 to £122,000, said the bus services were "generally used by elderly and disabled people".
The report, authored by the council's public transport department, said: "With the withdrawal of services, access to supermarkets will be reduced and residents may have limited access to low cost food.
"It may also result in increased social isolation."
The use of shared taxis or community car schemes is to be investigated as an alternative.
In a separate proposal three cameras could be installed above bus lanes, fining motorists £60, or £30 if it is paid early, if they use the lane unlawfully.
Elderly people could become more isolated as bus subsidies are cut in a bid to save £100,000, according to a council and campaigners.