Lincolnshire County Council health watchdog voted to refer the ongoing overnight closure to Jeremy Hunt.
The Grantham and District Hospital first reduced the unit's opening hours in August.
Melissa Darcy, of Fighting 4 Grantham Hospital, welcomed the decision and said it was the "best scenario and outcome of the meeting".
The A&E department currently only opens from 09:00 to 18:30 daily.
United Lincolnshire Hospital Trust, which is in charge of Lincolnshire's hospitals, said in September it was trying to recruit more doctors and would fully reopen Grantham's A&E as soon as possible.
Christine Talbot, chairman of the Health Scrutiny Committee, said: "We do not believe that overnight A&E services will be reinstated by February 2017, in fact the committee concluded that although indicated as temporary, the closure is in effect permanent."
The trust said closing Grantham would enable to it maintain safe staffing levels at its two other A&E departments, both of which take a higher number of patients.
Lincolnshire Community Health Services NHS Trust operates a daily walk-in service for minor injuries between 18:30 and 23:30 at the hospital.
The trust said this service was not a replacement for the A&E department.
The decision came at a meeting in Lincoln as anti-closure demonstrators gathered to protest.

Police, councils and the NHS recorded scores of missing items, including computers, mobile phones, Blackberries and USB data sticks.
The call for action came from the Lib Dems who obtained the information.
The Scottish government said public services were responsible for storing their own information.
The Lib Dems said that between December last year and June, seven NHS areas recorded a range of missing equipment, including patient files and details of more than 100 people on a needle exchange programme.
Greater Glasgow and Clyde NHS board reported the theft of eight laptops, six hard drives and three PCs.
This included two laptops stolen from the paediatrics department at Yorkhill Hospital in March of this year and a PC stolen from the X-ray viewing room at the Western Infirmary in April.
Meanwhile, Strathclyde Police reported an unencrypted USB stick containing investigation files as missing.
Lost or stolen equipment among local authorities included five laptops from a children and families establishment in Edinburgh which contained the details of 10 people.
West Dunbartonshire Council also lost 60 personal computers from schools.
Most equipment missing from councils was either encrypted or contained no personal details.
Last January, the Lib Dems called for an urgent review into data loss after reporting that scores of laptops, PCs and memory sticks containing confidential data had been lost by councils and health boards in recent years.
The party said that while almost all files were encrypted, the public would be rightly worried that their personal data was at risk.
Lib Dem justice spokesman Robert Brown said: "Central government, local councils, NHS boards and the police hold a great deal of information on all of us. Our data is in their hands and we need to know they are taking this responsibility seriously.
"The government is not in control of the situation. They need to get a grip on this right now."
A Scottish government spokesman said it took data security "very seriously" and had set robust standards for the storage and transmission of data.
He added: "We expect the same high standards of public sector bodies. However, it remains the responsibility of individual police forces, local authorities and health boards to ensure that personal or sensitive information is stored securely."
The closure of Grantham's A&E services due to a lack of doctors is to be referred to the health secretary.
[NEXT_CONCEPT]
Scottish ministers have been told to "get a grip" of data control as new claims emerged of equipment being lost or stolen from the public sector.