Labour is launching a new policy to reverse cuts to 3,000 bus routes in England and Wales.
The party said the £1.3 billion per year policy would be funded by revenue from Vehicle Excise Duty.
But Conservatives claimed that Labour would have to “clobber motorists with tax hikes and slash funding for road repairs” to pay for the move.
Labour leader Jeremy Corbyn will say bus services have been “devastated by nine years of austerity” as he visits Nottingham to launch the policy on Thursday.
Analysis by the Campaign for Better Transport shows more than 3,000 bus routes have been cut back or withdrawn since 2010, amid a 45% reduction in local authority bus budgets.
In a speech, Mr Corbyn will say that bus services are a “lifeline” for many people.
He will add: “Cuts have had disastrous consequences for our towns and city centres and for air pollution and the environment.
“Bus networks are essential for towns and cities and for tackling rural poverty and isolation, which is why Labour is committed to creating thriving bus networks under public ownership.
Conservative vice-chairman for local government Marcus Jones said: “Labour have already spent the pot of money they claim would fund this proposal, meaning they would have to clobber motorists with tax hikes and slash funding for road repairs to pay for it.
“Along with their plans to put politicians in Westminster in charge of running local bus services, their pledge to slash funding for roads and their calls to increase fuel duty, this just proves they are not on the side of hard-working families who rely on their vehicles.
“We already spend a billion pounds every year to provide free bus travel to those who most need it most and have empowered local communities to bring about changes to bus services and improve services for passengers.”
Department for Transport figures show the number of local bus passenger journeys in England fell by 85 million or 1.9% to 4.36 billion in the year ending March 2018.
Free bus passes for off-peak travel are a legal entitlement for people aged over 65, or those with a disability.
Budgetary constraints mean councils are spending less on discretionary items such as free peak travel, post-school transport and supported rural services.
Nearly half of all bus routes in England receive partial or complete subsidies from councils.
The Local Government Association has warned these services are at risk as local authorities will struggle to maintain current levels of support unless they are given more funding.