南約克郡第一公司的總經理Nigel Eggleton說，該公司必須對 "大流行病後的需求變化 "做出反應，包括在家工作的增加。
Oliver Coppard said services will be reduced by a third after a tender process for some routes ended with no operator agreeing to take them on.
No bus operator agreed to take over a number of routes on behalf of the South Yorkshire Passenger Transport Executive in the tender process which closed this week.
Mr Coppard, who was elected in May, said: "These cuts will strike at the heart of our families, our economy, and our communities.
"They will also unfairly impact on those with mobility and health issues who rely on these bus services as lifelines."
Nigel Eggleton, managing director at First South Yorkshire, said the company had to respond to "changes to post-pandemic demand", including increased working from home.
He said: "If private operators won't run our bus services, then the mayor has to be allowed to run them as a public service."
The Department for Transport said it was investing £3bn into bus services by 2025 and had awarded us operators and local authorities almost £2bn since March 2020 to mitigate the impacts of the pandemic.
South Yorkshire has been allocated £570m over the next five years as part of the City Region Sustainable Transport Settlements to fund local transport within the area, including buses, it added.
She said if further funding is not provided, from October, South Yorkshire could be left with only four bus routes running across the region after 10pm.