The current bill was a major step backwards for the present world-class education system, he said.
"On one hand you have a strict regulatory body which is gate-keeping the standards for our teachers in our public education system and on the other hand you have an 'education' bill that will foist completely unqualified teachers on our most at-risk students in low socio-economic areas in the country."
Trying to make any sense of it was a bit like saying "let's build a new hospital in a low socio-economic area then staff it with unqualified doctors", he said. "Well now that really makes sense doesn't it?"
Charter schools would be fully funded from the public education budget. They would have to accept pupils on a first-come-first-served basis. They could not select pupils.
Unlike State schools, charter schools would not have to give preference to pupils in a designated zone. They would be able to accept them from anywhere. If a charter school received more applicants than it was allowed to enrol, it would have to hold a ballot.
Like State schools, the charters would have to provide the national curriculum and qualifications. Their contract with the Education Minister would state their required performance standards and reporting obligations.
But Mr Ewing said the proposal missed the point that New Zealand teachers were respected worldwide for their dedication, work ethic, caring nature and top academic qualifications.
"Yet this ill-conceived, shoddy legislation which has no mandate from the voting public completely ignores the number one factor that leads to first-class education and that is teacher quality."
He said there would be no requirement for the principal of a charter school to be a qualified teacher. Instead a principal would be a "professional leader".
This week New Zealand Education Institute national president Judith Nowotarski told the select committee charter schools represented a dangerous and damaging ideology that had no place in New Zealand's quality public education system.
Charter schools had been tried in other parts of the world such as the United States and the UK. They had not provided better education for vulnerable children. On the contrary, evidence showed that allowing private, profit-driven and unqualified people into the education system would undermine quality education, she said.
"Poverty and inequality are the two leading causes of student underachievement. Proposals to bring in charter schools are a diversion from addressing the real issues."
If the legislation is passed, Wanganui could find itself home to one of the first of the partnership schools. Formerly at Wanganui Boys' College, Alwyn Poole has been reported as wanting to set up a school in Wanganui.
He said he had support from Wanganui businesspeople and had found suitable land for the school, which would take Year 7 to 10 students.
Mr Poole is the principal of Mt Hobson Middle School in Auckland, a private school with 60 students and low teacher-student ratios. He is looking to extend the Mt Hobson model to Wanganui once the legislation is passed.
He said he was considering Wanganui as he still had family here and grew up in the city.