PM Turnbull finally finds his voice

The prime minister took two weeks to deliver a piece of lyrical advice to Treasurer Scott Morrison, but he's now done it.

Malcolm Turnbull finally correctly recalled the lyrics to The Voice at a Perth radio station. (AAP)

He finally found his voice.

Two weeks after stumbling over the lyrics of a classic John Farnham track, Malcolm Turnbull nailed the line.

"The good line in The Voice of course for the Treasurer is 'We've got to make ends meet before we get much older'," Mr Turnbull told Perth radio Mix 94.5 on Friday.

"That's the classic line. I was struggling to remember that the other day on radio."

On 3AW a fortnight ago the prime minister couldn't find the right words to make his noise and make it clear.

"There's a good line in there for the treasurer - time to um, what is it ... the bit about balancing the books," he said.

Host Neil Mitchell jokingly asked whether it was the lyrics about looking "down the barrel of a gun".

The federal budget will be delivered on May 8.