One of the country’s biggest providers of agency health workers has been accused of “profiteering” after trying to charge care homes up to £2,700 to supply a staff member for a single shift.

The Guardian can reveal that Newcross Healthcare, already exposed for fining workers £50 when they call in sick, quoted the sky-high charges in a price list sent out to homes looking for cover over Christmas.

Newcross – which supplies thousands of agency health workers to care homes, many of whose residents have their fees paid by local councils – stated that it would be charging triple its normal Sunday day rates to supply staff on Christmas Day and Boxing Day.

According to a price list seen by the Guardian, the firm normally charges £76.84 an hour to supply a head of care, also known as a matron, for a Sunday day shift. At triple rates of £230.52 an hour, this would cost a care home £2,766 for a 12-hour shift.

The company also charges £59.12 an hour to supply a nurse for a Sunday day shift. At a triple rate of £177.36 an hour, it would mean a 12-hour shift for a nurse would cost a care home £2,128.

A normal Sunday rate for a senior carer is £30.12, the document states.

The Labour MP Barbara Keeley, the shadow minister for social care, said: “It is symptomatic of the broken social care system caused by Tory austerity measures that companies like Newcross Healthcare can effectively fleece the taxpayer for thousands of pounds just for a single shift.

“This cynical company puts a high price on the work of their staff but values them far less, fining them for calling in sick and eroding their terms and conditions.”

It follows a Guardian investigation which revealed how Newcross Healthcare, which made a pre-tax profit of £21m in 2017, has been fining staff who phone in sick £50, raising concerns that frontline employees are being forced to turn up for shifts when they are not fit for work and risk spreading illnesses to vulnerable patients.

After the Guardian’s investigation in December, the firm said it would scrap the policy in April but has faced calls to end it immediately.

Following our story, a concerned care home manager contacted the Guardian after being sent through an email about the Christmas period rates. The correspondence stated that the firm would charge double Sunday night rates from 6pm on Christmas Eve until 8am on Christmas Day, before upping the charge to triple Sunday day rates until 8pm and triple Sunday night rates until 8am on Boxing Day.

New Year’s Eve from 6pm until 8am on New Year’s Day was charged at two-and-a-half times the normal Sunday night rate, before dropping to twice the Sunday day charge until 8pm. Sunday night hourly rates are slightly lower than day shifts, with £71.37 charged for a head of care and £54.90 billed for a nurse.

The care home manager, whose home looks after people funded both privately and by local authorities and the NHS, said Newcross was “exceptionally cut-throat in the way they do business”, accusing the firm of “profiteering”.

The manager, who did not wish to be named, said: “Any opportunity to squeeze the customers a little bit harder, they seem to want to do so. I don’t think there’s any consideration given to who they’re charging. Whether it’s a top-end private provider that’s getting £1,500 a week to look after a resident or whether it’s a local authority provider where the fee levels are much less.

“They don’t just charge triple rate [for Christmas Day], it’s triple the Sunday rate. That’s pretty poor. I deal with three or four agencies at the moment and none of the others do that. In comparison to them, they are profiteering.”

The manager said other agencies he used typically charged double their normal rates for these periods. He said he managed to find cover from another agency, meaning he did not have to pay Newcross’s Christmas rates.

The manager also said Newcross charged inflated “introduction” fees for care homes wanting to employ nurses or carers who work for the agency. “General practice is for agencies/recruitment companies to charge 10%-12% of salary for a staff member who leaves them to work for a client so I’d typically expect to pay up to £1,500 for a care assistant or £2,000-3,000 for a nurse. However, Newcross charges a fixed fee of £3,000 for a care assistant or £6,000 for a nurse,” he said.

He added: “Their terms and conditions even try to hold clients responsible for this fee if they recommend a member of Newcross’s staff to a third-party employer who subsequently employs them … My feeling is that they simply want to make it as difficult as possible for their staff to leave without some kind of compensation for the subsequent loss of income.”

Newcross Healthcare did not respond to repeated requests for comment.