The temporary closure of a Muslim free school has raised serious questions about ministerial oversight of the creation of the Government's flagship institutions, Labour said.
Shadow education secretary Stephen Twigg said swift answers were needed about the Al-Madinah school in Derby, which is due to reopen tomorrow.
In a letter to Education Secretary Michael Gove, he said the situation must be "clarified urgently in order to reassure the public".
The school, which opened in September last year but closed its doors on Tuesday just hours after Ofsted began an inspection, h as faced accusations of introducing strict religious practices.
Interim principal Stuart Wilson took the decision to shut the school on health and safety grounds after inspectors shared their initial findings with him.
He insisted that he acted to address a "short-term health and safety issue that has now been completely resolved and will not reoccur", and not on the instructions of inspectors.
While Ofsted's findings have not been finalised, reports suggest the watchdog will judge it "inadequate", the lowest rating.
Recently there have been reports that female teachers at the school - which claims a "strong Muslim ethos" - were forced to wear hijabs even if they were not Muslim.
Other reports claimed that girl pupils were made to sit at the back of the classroom and boys at the front.
Mr Wilson told the BBC he had not received any complaints from colleagues over the school's dress code and denied that pupils had been split up.
In his letter, Mr Twigg told Mr Gove: " This is, of course, not the first time that there have been questions surrounding your department's oversight of a free school.
" While I understand that there is an ongoing investigation, the reports concerning this school are of extreme concern to parents and the wider community.
"Given the confusion as to why the school has closed, and that pupils may be returning to the school on Monday, I would ask that these matters be clarified urgently in order to reassure the public.
He asked what "due diligence" was carried out when the school was approved, what oversight there had been since the school opened and whether there was " appropriate vetting" of teachers and staff.
Mr Twigg questioned what would happen to pupils if the school did not reopen tomorrow or closed again.
A Department for Education spokesman said: "We were already investigating this school before the allegations became public.
"We discussed the problems with Ofsted and it launched an immediate inspection. We are waiting for Ofsted's final report and considering all legal options."