The Australian Capital Territory government has cut its ties with the controversial multimillion dollar Teach for Australia program, citing concerns about the program’s value for money.

Guardian Australia can reveal the territory formally split with Teach for Australia in July this year, unhappy with the cost of the program and unconvinced it was “delivering classroom ready graduates that remain in the teaching workforce”.

Launched by the Gillard government in 2009, Teach for Australia provides graduates from non-teaching backgrounds with 13 weeks of intensive training before they begin a two-year classroom placement at a regional or low socio-economic school.

The program has been hugely controversial since its inception. While successive governments have increased its funding, teachers’ unions have long criticised its costs and retention rate and argued it undermines the teaching profession by placing teachers who have not yet completed their qualifications in schools.

The ACT’s education minister, Yvette Berry, told Guardian Australia the decision to withdraw from the program was based on “two main factors”.

“The first of concern was the low retention of participants in the teaching workforce compared to the investment required to collaborate with TFA,” Berry said.

“The second of which is the ACT government’s focus on investment in strengthening initial teacher education, support for new graduates, and growing the existing workforce capability as one strong cohort of educators.”

But in questions to the ACT education department, a spokeswoman admitted cost had also been a factor. Guardian Australia understands the ACT paid about $15,000 for each new Teach for Australia graduate, while the commonwealth has committed $77m to the program between 2009 and 2021.

“Yes, on balance the TFA model proved costly without strong evidence of delivering classroom-ready graduates that remain in the teaching workforce,” the spokeswoman said.

With the ACT’s departure, Teach for Australia remains in Victoria, Western Australia, Tasmania and the Northern Territory. New South Wales, the state with the country’s largest teaching workforce, has refused to join since the program was launched.

In a statement the Teach For Australia chief executive and founder, Melodie Potts Rosevear, said the organisation was “very proud of what we have achieved in the ACT”.

The program, she said, had made “a significant contribution to reducing educational disadvantage over the past eight years, and will continue to support the active associate and alumni community in the region”.

“Our growth strategy is to partner with jurisdictions across Australia to place our associates in schools that are experiencing the most disadvantage,” she said.

“Next year will be our largest intake of associates yet, with growth in teacher placements across Victoria, WA, NT and Tasmania – with nearly half in regional and remote communities.”

The program has maintained the support of federal governments from both sides of the aisle since it was launched.

When a government-commissioned evaluation of the program released last year found Teach for Australia associates “outperform other early-career teachers” against professional standard measures, the then-education minister Simon Birmingham said its teachers were “helping plug the gap in disadvantaged Australian secondary schools”.

But the report also raised concerns about the Teach for Australia attrition rates and the placement of teachers.

While the program is designed to place graduates in socially disadvantaged schools, the evaluation report found that 13% of its associates worked in schools above the national disadvantage median.

It also found that three years after the placement had finished, less than 50% of graduates were still teaching. Only 30% of those left were in schools below the national disadvantage median.

While the ACT government spokeswoman said there had not been a formal review of the program, it had concerns about the attrition rate of the program’s associates.

“Of the associates in the ACT public system only 50% of 38 graduates engaged to December last year were still employed by the department,” the spokeswoman said.

“Of these, 10% had transferred to schools not identified as low socio-economic status. In prior years the retention rate has been as low as around 25%.”

The Australian Education Union has been one of the program’s most vocal critics since its launch. Correna Haythorpe, the union’s secretary, said it had been a “crushing failure”.

“TFA has failed to deliver any real boost in teacher numbers, with attrition rates high above the qualified workforce rate,” she said.

“The Turnbull government’s own evaluation of the TFA showed that one third of participants had left teaching only one year after becoming qualified teachers. Within three years more than half the participants had left teaching altogether.”