Paying teachers more as they progress up the ladder will keep them from walking away from what is now a lonely profession of freelancers, a NSW parliamentary inquiry has heard.

An upper house committee is investigating how to combat the shrinking supply of school teachers, a problem felt across the country that has now drawn the federal government’s focus.

University of Melbourne Professor John Hattie, an authority in the education field, told the committee on Wednesday a lack of a financial incentive tied to career progression was a contributor to teachers leaving their jobs.

‘‘The biggest issue we have in terms of attraction to the profession is not the starting salary … but it’s what happens about 10 years into the profession,’’ he said.

‘‘It goes very flat and it’s not a great incentive to join a profession where after 10 years you kind of struggle.’’

He noted fresh graduates were on short-term contracts for the first five years of their working life, which drives them away from seeing teaching as a long-term career.

The renowned expert is working with the New South Wales government on a plan to bring a level of prestige to the teaching profession, which unions say has been lost in recent decades.

NSW Teachers Federation head Angelos Gavrielatos told the committee earlier this month the state had let its students down.

A government proposal to pay top performers more has been criticised for pitting teachers against each other, while plans for pre-written lessons have little support because teachers enjoy that aspect of the job.

Dr Hattie said teaching had become lonesome, with professional development and mentoring taking a back seat to teachers trying to keep up with administrative tasks and cumbersome workloads.

‘‘Teaching has been a lonely profession … We have been in a sense individual contractors,’’ he said.

‘‘We cannot afford to have a profession of only individuals, no matter how expert they are moving forward.’’

A greater focus on retention of teachers by policy makers was needed, Dr Hattie said.

Keeping teachers in schools has become a national agenda item.

Federal Education Minister Jason Clare met state and territory counterparts in Canberra last week to discuss how to fix the crisis.

The meeting canvassed multiple issues, including labour shortages, workloads and retention issues.

It also considered incentives for people wanting to make a mid-career change to teaching.

Of the nearly 11,300 teachers and administrators surveyed in NSW, about 60 per cent said they planned to leave the profession in the next five years.

The online survey was commissioned by the upper house committee.

-AAP