Plumbing, electrical trades, disability, aged care and childcare will be among the courses initially covered by the 10-year plan, which Labor says will be modified each year to plug gaps.

"This government is deliberately killing TAFE and we need to rescue it," opposition leader Michael Daley said in Sydney.

"Free TAFE will not only help teach young people the skills they need but also offer older people who've lost their jobs the opportunity to retrain - and retrain free of charge."

Students will only be able to access one fee-free course.

The first four years of the plan have been costed at $65 million by the parliamentary budget office.

But Labor can't say how many places that money will cover.

"The 600,000 places will be phased in over time," Labor's TAFE and skills spokeswoman Prue Car told reporters.

"Everyone who applies to do a course in one of the areas identified will be able to study for free."

Private providers will only be able to make up 30 per cent of the total funding pool and will be overseen by a specific investigations unit to examine student complaints.

Labor says the policy will apply from January 2020 and will replace the government's Smart and Skilled subsidy for 100,000 apprenticeships over four years.

Daley said he would sunset the current scheme to ensure those already enrolled aren't out of pocket.

Deputy Liberal Leader Dominic Perrottet said the Berejiklian Government was already delivering almost 80,000 fee-free TAFE places each year.

"Labor’s announcement ... will fall well short of what we are already providing," Perrottet said in a statement.

The auditor-general in July 2018 recommended the primary industries department use data better to ensure only high‑priority qualifications were covered by the Smart and Skilled scheme.

AAP