Most world leaders get a chance to vocalise their thoughts daily thanks to the 24-hour news cycle. Others prefer to tweet.

But for Australia's early prime ministers, like Billy Hughes, Stanley Bruce and Earle Page, an important way to speak to voters was through a record player.

If you've ever wondered what they sounded like, the Museum of Australian Democracy (MOAD) at Old Parliament House has an answer.

Rare recordings of these PMs, some of which date back to 1929, were discovered by MOAD curatorial officer Campbell Rhodes for sale on eBay.

"We've bought quite a few things that way before," Mr Rhodes told ABC Radio Canberra's Dan Bourchier.

"They all spoke with what we call received pronunciation, which is sort of BBC English.

"It was very common to speak like that on radio or in public for quite a long time well into the 1950s and 1960s."

Hanging on every word

The museum has had the records professionally digitised so they can be enjoyed for many years to come.

"It's interesting to hear their voices and discover what they sounded like," Mr Rhodes said.

He described Billy Hughes, who was prime minister from 1915 to 1923, as having a very appealing tone.

"You can see why his audience liked him ... he had a very fiery temperament and you can imagine his audience hanging on his every word," he said.

Billy Hughes, the seventh prime minister of Australia, was in office from 1915 to 1923. ( Supplied: National Library of Australia. )

"Then you had Menzies who was a very good orator as well; he had quite a soothing and calming voice.

"Then you have people like Ben Chifley, who has a voice which was described by someone as ... harsh, uninflected and inclined to grate on the ear.

"Not only did he have a very Australian recognisable voice, but he had a very gravelly voice.

"It's kind of charming to listen to now."

Mr Rhodes said Ben Chifley's voice was once described as being harsh on the ear. ( Supplied: State Library of Queensland. )

Mr Rhodes said these speeches were recorded inside a studio rather than in front of a live audience.

He said many were produced by Columbia, one of the biggest record companies at the time.

"I believe they recorded their speeches to the microphone so they could distribute it out to more people; they were sent out to people and you could buy them," he said.

Further recordings remain undiscovered

Today, Mr Rhodes said it was much more acceptable for prime ministers and other world leaders to use their natural speaking voice when speaking in public.

"The craft of crafting a political message is the same but the medium has changed," he said.

"These days, of course, everything is always recorded. The 24-hour news cycle means every utterance is on camera and recorded for all time."

Interestingly, Mr Rhodes said there were no known recordings of Australia's first five prime ministers: Edmund Barton, Alfred Deakin, Chris Watson, George Reid and Andrew Fisher.

"You can't hear the first five because as far as we can tell there are no recordings ... but [if there are] we would love to hear them," he said.

He urged anyone who had recordings of these leaders to contact MOAD or the National Film and Sound Archive.