That could include pulling out of Oxford's entire network of Park & Ride routes.
The Oxford Bus Company and Thames Travel have put out an urgent appeal for the Government to extend its Bus Recovery Grant, warning they may have to cut up to 30% of journeys if the support ends.
Bus firms have had help throughout the pandemic, but the support runs out on April 5th, and there's been no word yet on any financial help beyond that date.
The Oxford Bus Company and Thames Travel say 'significant cuts' would include withdrawing the entire Park&Ride network, some Oxford City services and certain rural services.
And, they have just a few weeks to make a decision. If they're going to reduce services they have to give 35 days notice, which makes the deadline February 25th.
The emergency funding has enabled operators in Oxfordshire to provide service levels at least 90% of pre-pandemic service levels. But, current usage is only at 70% of pre-pandemic levels.
Phil Southall, Managing Director of Oxford Bus Company and Thames Travel said: "There is a real threat we will have to reduce services by around 20% to 30% in three weeks' time.
"We are on a cliff edge and at a time when people need services to return to work, education and leisure activities it is absolutely critical government extends its support."
In response, a Government spokesperson said: "The government has provided an unprecedented £1.8bn in support to over 160 operators to keep services running during the pandemic, and we're working closely with the sector to understand the potential challenges and mitigations once it ends in April."
In addition to the withdrawal of Bus Recovery Grant funding, the Department of Transport has issued guidance to local authorities indicating emergency funding for concessionary travel to operators can be reduced from April 1st.
The funding is used for operators to carry eligible passengers for free such as senior citizens.
According to the Oxford Bus Company and Thames Travel, Oxfordshire County Council has paid 100% of the funding to bus operators to date - but 'this could now be reduced to 65% of pre-pandemic levels over the next 12 months or so, even though it will continue to receive 100% from government.'
Phil says they need Oxfordshire County Council to continue to pay 100% of pre-pandemic levels for carrying concessionary passengers - so some services under threat can continue, even if Bus Recovery Grant funding is withdrawn.
Oxfordshire County Council says it 'fully supports the bus industry in its request for further Government funding to maintain the network.'
A statement added: "Since the original support package was announced last year, patronage has been suppressed by the Omicron variant and has not recovered as anticipated.
"The Council is working closely with operators to fully understand the potential impact on bus services, but urges the Government to make swift decisions on future recovery support and the outcome of our Bus Service Improvement Plan.
"No decisions have been made but the council's current plan is to follow DfT guidance in supporting the network through the payment of concessionary fares reimbursement in the 2022/23 financial year, as per the approach of many other local authorities."
Mr Southall added: "Like all bus operators in the UK, we need the government to extended Bus Recovery Grant funding by another six to nine months while we seek to continue to rebuild patronage."