It's estimated NSW could save about 500 lives and up to $1.3 billion every year if authorities boosted influenza vaccination rates for people aged under 65.

A NSW Productivity Commission report, released on Friday, found at least $500 million could be saved statewide annually if 55 per cent of under 65s had a yearly flu shot.

At present, 25 per cent of the cohort gets an annual flu jab, the commission said, forecasting the overhaul would mean vaccinating up to two million more people per year.

The approach would alter current public health strategies that focus on vaccinating people aged over 65, young children, pregnant women and those with compromised immune systems, it said.

The agency, which works to drive state productivity improvements, found that every extra jab on the way to the target would save between $250 and $640.

Productivity Commissioner Peter Achterstraat said evidence from overseas showed a mass vaccination approach could work.

"The effective vaccine we have already saves lives and limits the financial cost of influenza, but more can be done," Mr Achterstraat said.

"Ontario, Canada expanded their flu vaccination program to include young and healthy people in 2000. Since then, flu-related deaths fell by almost three quarters.

"In NSW each year, deaths from influenza-like illnesses range between 6-12 deaths per 100,000, depending on the severity of the flu season."

The commission said the economic benefit from mass vaccination would range between $500 million and $1.3 billion annually depending "on factors like vaccine uptake among different groups".

NSW's flu season, still underway, has been relatively severe with more than 85,000 cases reported. The state reported 116,000 influenza cases across the 2022 flu season.

Some 308 people died from influenza in NSW last year, NSW Health data shows.