Trinity Grammar School will see Ashfield Council in the Land and Environment Court on Tuesday – a week after councillors voted not to support its request to increase the number of pupils at its Summer Hill site by 200 students.

The Scots College at Bellevue Hill is due to face off against Woollahra Municipal Council next month after the council failed to approve its application to increase the number of students covered by an enrolment cap at its Victoria Road campus by 350 pupils.

Scots, which is being taken to court by a residents' group that claims the school is already breaching its existing 1120 student limit, has also launched a separate court action against council for refusing its plans to expand its nearby early learning centre at Kambala Road.

A Year 12 student attending either school would pay about $30,000 a year in fees.

Trinity’s latest court date comes after Ashfield Council voted on Tuesday night to defer any decision about its student numbers until the school’s latest building project has been running for 12 months.

The school is constructing a multimillion-dollar aquatic centre – complete with an Olympic-sized pool, stadium seating, gymnasium, offices and extra classrooms – that will loom up to four storeys high behind adjoining properties.

The vote went against a staff report that recommended council approve increasing Trinity's maximum student numbers from 1500 to 1700.

‘‘We wanted to see what impact that had on the local community before we were prepared to support any increase in student numbers,’’ said Ashfield’s deputy mayor, Caroline Stott, who added the school’s existing size was already causing traffic problems for neighbouring streets.

‘‘The situation is horrendous now and it’s very hard to understand how the local roads could handle any increase in numbers.’’

Although Trinity has previously been granted planning approval for a smaller underground pool complex, it used a state infrastructure policy to bypass the need to consult the council or community about the expanded proposal.

The new complex, containing what will be the school's second pool, was approved by certifiers Dix Gardner.

Resident Marilyn Wise, who described the school’s original design as ‘‘relatively benign’’ compared to what it was now building, said the school had concealed its plans from those likely to be affected by the complex.

‘‘The only notification we had received from the school was a letter saying that they about to begin construction, of what we weren’t advised,’’ she said. ‘‘We’re furious with the conduct of the school.’’

Neither Scots principal Ian Lambert nor Trinity’s Milton Cujes were available to comment on Wednesday.

Dr Lambert has previously rejected claims the college is in breach of its student cap or was seeking to ‘‘significantly change’’ its student numbers.