Councils for Worthing and Adur said they were left with budget shortfalls
Two Sussex councils are among more than 30 local authorities who claim providing free bus passes to over-60s has left them with budget shortfalls.
Free off-peak bus travel for over-60s and disabled travellers was extended in April to cover travel anywhere in England using a single pass.
A £212m government grant was made, but many councils - including Worthing and Adur - told the BBC it was not enough.
The Department for Transport (DoT) said funds were agreed with councils.
A DoT spokesman said: "We are now spending around £1bn on concessionary travel each year, including an extra £212m to cover the extension introduced in April.
"This new funding is allocated based on a formula that local authorities requested and takes into account people who travel to popular tourist towns and coastal areas."
Adur Council said it had a government grant of £167,000, but a shortfall of £238,000.
A statement said: "No specific services have been cut we have adjusted our budget accordingly to cope."
Worthing Council said it received £357,000 in government funding, but had a shortfall of £606,000.
It said expenditure was reduced last year by more than £1m.
But a statement added: "This cannot be specifically linked back to the saving required to fund concessionary fares as it was part of an overall package."
There are 322 local authorities in England. About 100 were contacted by the BBC about the impact of the bus passes.
Of those that responded, 10 had no problems, seven were still calculating the cost of the service, and 33 had shortfalls which they directly attributed to the scheme.