Notts County Council confirmed the working group will examine options at Retford Oaks School, which it says has a 'large number' of extra school places, like other sites in the area.
It is predicted that by 2014, the district as a whole will have well over 1,000 surplus places in its schools, says Retford Oaks' head teacher David Rich.
Mr Rich added that the group is not considering closing the site and that he is expecting the school to expand in the next few years.
The county authority explained more about the working group.
"(We have) a statutory responsibility for the management of school places and in particular schools that have large numbers of surplus places," explained John Slater, Director for Learning and Achievement at the council.
"A group of officers have been asked to look at issues with surplus places at Retford Oaks and this group is looking into all possible options to help manage the situation.
"At the moment no decision has been made."
Coun Phillip Owen, the new cabinet member for Children and Young People's Services, will work with senior officers to examine the options in detail, added Mr Slater.
Mr Rich, who is leaving Retford Oaks in the summer, said the group has been meeting since this time last year.
"The working party has been meeting since June 2008 to consider the current surplus places at the school in the context the large overall surplus of secondary school places in Bassetlaw," he said.
"The rapid rise in standards at Retford Oaks together with a 45% rise in the number of Year 7 students joining in September means the outcome of the deliberations will be further expansion of the school over the next few years."
Low numbers in the primary school section of Serlby Park School in Bircotes, which covers 3-18 year-olds, is also being looked at.
The school's headteacher, Jo Edwards, explained: "Our secondary school has no problems with numbers, in fact, we were over-subscribed last year.
"There are low numbers in our primary school but that is in line with birth rates across the country."