New Zealand Principals Federation president Philip Harding said he "totally concurred" with Mr Robertson's concerns.
School principals, together with leaders in the community, staff and Boards of Trustees needed to provide feedback on the scheme.
Education Minister Hekia Parata said a working group had been set up to work on the design of the initiative to help ensure it could be successfully implemented from next year.
Ms Parata said members supported the main features but also identified areas where more work is needed.
She also said the extra pay was for "delivering new functions" and was not dependant on the staff meeting performance outcomes or targets.
PPTA president Angela Roberts said supporting effective classroom practice with time and professional learning and development was positive for students.
"The bottom line is schools are going to get funding and staffing to assist them to collaborate with other schools. It's about freeing teachers up to support each other and the evidence internationally is very clear - when teachers are able to collaborate and support each other all of the kids are better off."
What is proposed under Investing in Educational Success?
*The Government has set aside $359 million over the next four years for developing new collaborative teacher and principal roles to raise student achievement.
*Three new teacher and principal roles will be developed within schools and come with salary increases.
*The new roles will use expert teachers and experienced principals in mentoring and support roles through clusters of about 10 schools to create a "community of schools".
*Experienced principals will also be attracted to struggling schools with a proposed additional allowance of $50,000 a year on top of the salary the recipient school offers.