Australian shares ended flat with a negative bias on Wednesday, as inflation data supported the Reserve Bank of Australia's cautious stance about future rate cuts.

The S&P/ASX 200 Index was little changed to close at 8,396.9.

Annual headline Consumer Price Index inflation remained at 2.4%, defying expectations of a slight decline, while the trimmed mean CPI edged up to 2.8%, above forecasts for no change, according to a report by the Commonwealth Bank of Australia.

"So far, there's been no smoking gun for the RBA to deliver another 25bp cut in their July meeting. We maintain our base case that the RBA will want to deliver further cuts in a cautious way," CBA Economist Stephen Wu said in the report.

On the domestic front, total construction work done in Australia in seasonally adjusted terms remained flat at AU$74.43 billion in the March quarter compared with the December 2024 quarter, data from the Australian Bureau of Statistics showed.

In company news, the US Supreme Court on Tuesday declined to hear an Apache tribe's appeal challenging Rio Tinto Group's (ASX:RIO) and BHP Group's (ASX:BHP) Resolution Copper joint venture project in Arizona.

Mineral Resources (ASX:MIN) lowered its volume guidance for the Onslow Iron project in Western Australia between 7.8 million tonnes to 8.0 million tonnes from its previous guidance of 8.5 million tonnes to 8.7 million tonnes. Shares of the company fell 5% at market close.

MAC Copper (ASX:MAC) entered a binding scheme implementation deed with Harmony Gold Mining for the South Africa-based mining and exploration company to acquire all the shares in MAC Copper via a scheme of arrangement for $12.25 per share in cash. Shares rose 20% at market close.