Headteachers could end up working on Christmas Day to put in place “11th hour” plans for the mass Covid-19 testing of students from January, an education sector body has warned.

Sam Henson, director of policy and information at the National Governance Association (NGA), said more detail was needed by teachers on how new coronavirus testing systems would be implemented in schools by the new year.

His comments came after the Government announced secondary school and college pupils’ return to class in England will be staggered in the first week of January to help schools roll out mass testing of students.

Schools minister Nick Gibb has said the tests will be administered by volunteers and agency staff and details will be published next week.

Speaking to BBC Breakfast on Saturday, Mr Henson said teachers were “told at the 11th hour that they are going to have to deliver on something that they don’t have the detail for.

“What we’re going to end up with is headteachers and school leaders across the country working on Christmas Day and Boxing Day to put these plans in place.”

On Friday, the NGA, a membership organisation for governors, trustees and clerks of state schools in England, joined education unions and other professional associations in advising secondary schools and colleges they should not be forced to set up mass testing of students in January if they are unable to.

The guidance said: “Many of our organisations have been actively calling for such tests for some time.

“However, it is our view that due to the chaotic and rushed nature of this announcement, the lack of proper guidance, and an absence of appropriate support, the Government’s plan in its current form will be inoperable for most schools and colleges.”

Mr Henson told BBC Breakfast the responsibility for the systems put a “huge degree of pressure” on school leaders.

“We all want this, that’s not under question,” he added.

“I’m worried about the perception that this announcement has created. We’ve ended up in a situation where the public are led to believe schools have been told they have to do this and they’re being resourced to do this.

“We need to get the facts clear.”

According to a Department for Education (DfE) blogpost published on Thursday, armed forces personnel will support schools and colleges in planning the creation of testing sites.

It said schools and colleges will be provided with equipment to deliver testing, while the “reasonable workforce costs of state-funded schools, incurred to help set up and administer the testing, will be reimbursed”.

A DfE spokesperson previously said asymptomatic testing will break chains of virus transmission, help pupils and teachers avoid the need to self-isolate, and reassure parents about returning their children to school for the spring term.

They added: “We do not underestimate the challenges involved and scale of delivering this, which is why a cross-government operation is being mobilised to support schools and colleges.”