The federal treasurer wants older Australians to retrain and work longer to help improve the national economy.

Josh Frydenberg will use a speech this evening to say he wants higher employment rates for over-65s to help grow an economy burdened with debt.

"As a nation, we need to effectively leverage the three P's - population, participation and productivity - to meet this challenge," Mr Frydenberg will tell the Committee for Economic Development of Australia.

He will also reinforce the government's determination to deliver a surplus.

"At $19 billion per annum, our interest bill is more than double what we invest in childcare and nearly as much as we spend on schools," the treasurer will say.

"Our debt burden represents not just a cost to the budget and therefore every taxpayer, but also an opportunity cost as it constrains the government's ability to invest in other areas.

"If we don't remain fiscally disciplined today, the next generation will have to pick up the bill tomorrow."

This discipline would require calm and considered decisions, not "knee-jerk reactions" to economic events or requests for government funds.

Mr Frydenberg will tell the dinner crowd that workforce participation for over-65s was 14.6 per cent, up from six per cent 20 years ago.

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But he will say 80 per cent of education happens before Australians turn 21.

"This will have to change if we want to continue to see more Australians stay engaged in work for longer," he will say.

He will point to Australia's higher life expectancy, a growing national median age and the shrinking number of working-age Australians.

Australians aged 65 or over represent 16 per cent of the population.