Australians searching for financial advice will be more likely to find help than a high-cost loan shark after a Google advertising ban came into effect Wednesday.

Searching for terms like "borrow money" or "loan" have previously returned ads for short-term or payday loans from companies like Nimble and Ferratum.

Those loans can carry fees that equate to annual interest rates of more than 300 per cent.

But starting Wednesday, Google will not run ads for loans than last less than 60 days in an effort to protect users from "deceptive or harmful financial products".