Mike Ashley’s Sports Direct and House of Fraser chains have asked store managers to work at least once a week while under the government’s furlough scheme.

Ashley’s managers had also been asked to return to work – on reduced pay – on Monday, but the company did a U-turn on Sunday after the Guardian published details of the plan.

Staff told the Guardian they had been asked to volunteer to go into stores about one day a week since the entire store team were put on furlough last month.

Two managers said they had been told not to clock on when they worked in stores while on furlough – seemingly in breach of the rules of the scheme, under which the government covers 80% of staff pay. They said they had been asked to pack up store stock so it could be returned to the group’s warehouse and sold online.

“They are doing it secretly so people don’t know what they are doing,” one worker said.

Andrew Crudge, an employment law expert at legal firm Trethowans, said: “The guidance is quite clear. If people are being asked to work and that will create any revenue for the company that would be a breach of the provisions.”

He said workers could be furloughed and then brought back into work for a period before being put on furlough again but that could only be for blocks of at least three weeks.

Last week, staff were asked to return to work full time on Monday. In a conference call and messages to workers, seen by the Guardian, Ashley’s Frasers Group asked Sports Direct and House of Fraser managers to return from furlough full time on Monday on 90% pay.

They were told they were required in stores 10 hours a day on at least five days a week to return stock to the retail group’s warehouse in Shirebrook, Derbyshire, so that it could be sold online and to prepare stores for physical distancing measures for when they are allowed to reopen.

Managers were told that Frasers had seen non-food stores being allowed to open again in mainland Europe and believed the UK government could release shops from lockdown within three weeks.

But some managers told the Guardian they did not want to return to work on less pay while they feared being at risk of contracting coronavirus and did not believe they would be provided with sufficient protective kit or social distancing measures.

“Until the government says we need to go back and the protection is there I am not going,” one said. However, he added that he felt under pressure to go back to protect his job.

“Everyone is scared,” he said. “They are paying us low wages for a long time and we have been working overtime for years … Why do I have to be frightened and likely spreading disease if they are not giving us anything.”

On Sunday afternoon after the Guardian published details of the plan, managers said they had been told they no longer had to return to work.

The latest controversy comes after Ashley was forced to issue a public apology after he pressed the government to allow Sports Direct to remain open as other non-essential retailers closed, on the basis that selling fitness equipment made the company a vital asset to Britons stuck at home.

The company has meanwhile admitted that it struggled to enforce physical distancing measures to protect staff at its Shirebrook warehouse.

Frasers Group did not respond to requests to comment.