Daily Discussion, page-7209

It's not quite as black and white as that..

Of course, the selling and repurchasing of the same CGT asset within a short period of time – resulting in a loss – can in some cases just be as a result of rational investing and not driven by tax. The disposal and acquisition may be explicable by reference to market changes, for instance the improvement in share price and demand for the stock may also be regarded as consistent with the way in which taxpayers usually hold and realise investments. The disposal and reacquisition within a short period of time may be referable to a change in investor sentiment and market activity. This tends against the dominant purpose of obtaining a tax benefit (see example 6 of ATO tax ruling TR 2008/1).This ATO ruling states that there is no set period of time between sale and reacquisition in order for a sale to be classed as a wash sale. It will depend on the overall circumstances, as it should. By contrast, in the United States by way of example, there is a 61-day rule. A loss from selling stock or mutual fund shares is disallowed for federal income tax purposes if, within the 61-day period beginning 30 days before the date of the loss sale and ending 30 days after that date, you buy substantially identical securities.

https://taxstore.com.au/news/wash-sale-arrangements-under-scrutiny