It seems the only way is down for the Aussie

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The battered Australian dollar hit a three-year low of $0.90 on Thursday, and there seems no end to its vicious slump, with some analysts pointing to a 20 percent decline in the coming years.

"70 (U.S.) cents here we come," said Bill Smead, chief executive officer and chief investment officer of Smead Capital Management, who expects the Aussie dollar to trade at that level in the next two years.

(Read More: How low must the Aussie go before the RBA backs off?)

"We're avoiding anything commodity related," he said, referring to the currency's close correlation the resources sector, which has suffered a broad selloff this year on concerns of a China slowdown.

The Australia dollar, already down 14 percent so far this year, is having a particularly hard week on dovish comments from the Reserve Bank of Australia governor Glenn Stevens on Tuesday, which have led to markets now pricing in not just one, but two interest rate cuts by the year-end, according to Reuters.

(Read More: Can Rudd Stop the Rout in the Aussie Dollar?)

The bank is set to meet next week and the consensus view is that it will cut interest rates by 25 basis points to a record low of 2.5 percent.

Shane Oliver, chief economist at AMP Capital in Sydney, said that if commodity prices were to go lower from where they are now, then a low of $0.70 was possible over the next few years.

"My base case was for the Aussie to go to $0.80 over the next year, but we seem to be getting there a little faster," said Oliver. "The Aussie has lost support from high commodity prices... as it's now broken below 0.90 to the dollar I expect it has started a leg downwards."

(Read More: Aussie back to doing its job as 'shock absorber')

Ric Spooner, chief market analyst at CMC Markets, said he believed the RBA would tolerate the Aussie going much lower going forward.

"I think the Aussie will find a natural home between $0.80 to 0.85," said Spooner. That target represents a 10 percent decline from current levels.

"I don't think the RBA will be overly concerned if the Aussie undershoots or overshoots that level. Historically the RBA has continued to cut rates even when the Aussie is falling and it has always been relatively tolerant of a lower currency," he added.

—ByCNBC's Katie Holliday: Follow her on Twitter @hollidaykatie