Schools will be investigated if the Department for Education is "informed" that they are "in breach" of a "requirement" to have a daily "collective act of worship", schools minister Nick Gibb has said.
The DfE will remind schools found to be in breach "of their duty" and advise on how they can comply, he said.
Mr Gibb's comment came in response to a parliamentary question asked by Conservative MP Sir John Hayes.
In a written question submitted on 23 March, Sir John asked the secretary of state for education "what steps his department is taking to ensure that a daily act of worship is taking place in every maintained school."
Mr Gibb's written answer was published on 31 March. He said: "Every maintained school, academy and free school is required to ensure that collective worship takes place each day.
"If the department is informed that a school may be in breach of this requirement, it will be investigated. Where needed, the department will remind schools of their duty on this matter and advise on how this can be met."
Collective worship in schools 'is an archaic law'
In February, the UN Committee on the Rights of the Child had pressed the government to repeal its regulations on collective worship in schools.
Under the heading "freedom of expression, religion, association and peaceful assembly", the UNCRC document reads: "Please describe the measures taken to...repeal legal provisions for compulsory attendance at collective worship in publicly funded schools and ensure that children can independently exercise the right to withdraw from religious observance at school."
Humanists UK education campaigns manager Ruth Wareham said Mr Gibb's statement was "alarming":
"Compulsory collective worship threatens the freedom of religion or belief of children and their families and is totally out of step with the kind of inclusive education we should be offering in a diverse 21st-century democracy like the UK," she said.
"The fact that the government now appears to be saying it will enforce this archaic law to an extent that hasn’t been the case in over 15 years is particularly alarming."
The general secretary of the Association of School and College Leaders, Geoff Barton, criticised the "vaguely threatening" tone of the response on collective worship and said it is "uncalled for and yet another demonstration of the government’s heavy-handed approach to dealing with sensitive subjects".
He continued: “Schools will be well aware of the requirement to ensure that collective worship takes place each day and will have interpreted this in the best way they can to suit their own mix of students.
“The challenges of the pandemic may well have caused schools some issues in the delivery of worship and they may have had to adapt their approach accordingly.
“What they do not need is veiled threats of investigation into non-compliance from the government at a time when re-establishing the day-to-day pattern of education is their absolute number one priority.”