The Master's Apprentices were probably the 1st Aussie band to explore Progressive Rock, they do "Poor Boy", which is a blues song from 1926, in it I can hear the Blues along with the Rock and other flares this song has. I'm unsure about the date of the song though and I'm even unsure if they were called The Master's Apprentices at that point with the founding member Jim Keays initially calling his band The Mustangs, though I don't even know how long that name lasted before becoming The Master's Apprentices. 1965 seems to be the date stamped for that band.
Many of the early Master's Apprentices songs have a very Garage sound with Psychedelic twists there's even examples of Reversing the tape (e.g. at the end of 'But One Day'), which I think The Beatles started doing with 'Rain' in 1966. The Master's Apprentices had some Bluesy songs though, so they probably got their influence from bands like Them, The Rolling Stones, The Animals and The Yardbirds.
I think in turn Them, The Rolling Stones, The Animals and The Yardbirds had those Bluesy roots, though took on a Rock approach, 'For Your Love' from the Yardbirds interesting enough was when Eric Clapton decided to leave The Yardbirds because the song was too Commercial (or so I read), and felt the Band were moving away from their Blues Roots. Them feat. Van Morrison have those Blues traits depending on the Song - 'Baby Please Don't Go' is a classic example of that, though not necessarily found in 'Here Comes The Night' which seems to be a Slower Ballard Rock song, though I'm not sure what to make of 'Gloria', it doesn't come across as Blues, perhaps it's more responsible for the Garage Punk genre of the 60s, which were later become Punk in the 70s?
I have troubles defining what Progressive Rock is, is it the Progression bands did when moving on from Psychedelic, or are they simply recognised as Progressive because of each song they made? If it's the later then The Rolling Stones had those tendencies where each song would vary from a soft Ballard style to a full on Head Banging song. The Master's Apprentices started a bit differently as they were moving through the Psychedelic phase, though Progressed as the Band moved on to more gentler stuff and by 1970 their classic 'Because I Love You' doesn't even display that edgy music from their mid-60s material.