Member for Murray Helen Dalton has demanded the state government stop dragging its feet on teacher incentives for Griffith.
Mrs Dalton said up to 28 teacher vacancies needed to be filled at Murrumbidgee Regional High School.
She described the decision to create the new school as a "penny-pinching, cut price, poorly managed merger that has been a total disaster".
"We need a principal at both sites, but they won't put a principal on the other site because that would be an admission that the merger has failed."
She said teachers were under enormous pressure, and vacancies meant covering the entire workload was difficult.
"Teachers are doing it tough and the department is not giving the support the teacher's need," she said.
She said that pressure the teachers at the Griffith and Wade sites felt was helping drive teachers to other opportunities, schools or retirement.
"Every teacher which leaves take institutional knowledge," she said.
Mrs Dalton said a review of teacher incentives had been completed because the reviewing committee had been disbanded.
"It won't be released until term one but it should be released now so we can get something sorted in term four," she said.
Mrs Dalton said recruiting teachers to Griffith "had always been tough" which was why action was needed now.
"Unhappy teachers means unhappy students which means an unhappy community."
Mrs Dalton has launched a petition in a bid to force the government act - it requires 10,000 signatures from NSW residents.
She said she had attempted to work with the current NSW education minister Sarah Mitchell, by writing to her to advise of the issues she had heard about and inviting her to the city and school to see those issues first-hand.
Griffith's Teachers Federation members are set to meet on Monday to discuss teacher vacancies at Murrumbidgee Regional High School.
Federation president Angelo Gravielatos will visit the city for the meeting. It's believed Gonski Institute director and former education minister Adrian Piccoli is also expected to attend.
Federation organiser Brett Bertalli predicted that 30 vacancies would need to be filled at MRHS.
Mr Bertalli said those vacancies included resignations, transfers and promotions, or were temporarily employed staff..
"The problem is we started the year with 11 vacancies. It's gone on too long, the education of our children is at stake," Mr Bertalli said.
He said the federation was seeking commitments from the education department and state government and without them, industrial action would be considered.
"We need better incentives and need to address leadership issues across the school. One principal across two sites is not good enough."
While the Department of Education didn't confirm the number of teacher vacancies at the school, however MHRS executive principal David Crelley told parents in a term four newsletter that teachers 'came and went' during this time of year.
"It is important to recognise that these issues have existed for years and well before the new school started," Mr Crelley wrote.
"As has occurred every year the school has staff who are transferring, getting promotions, taking leave, retiring, taking up opportunities at other schools within the department of education or privately, being seconded into corporate roles within the department, moving out of education for personal reasons to pursue other roles or simply retiring."
Mr Crelley said the school was committed to filling all positions with permanent staff.
"Please be reassured that the school is actively recruiting to fill vacancies as they occur at this time of year similar to many primary, central and secondary schools," he said.
"We look forward to introducing new teachers with strong capacities to benefit students' learning outcomes."