Foster's made "misleading and deceptive" statements in its full-year results presentation, according to claims made by the drinks group SABMiller, which turned hostile in its A$9.5bn (£6.3bn) bid to take over the Australian brewer last month.
The accusation came to light in an announcement by Australia's Takeovers Panel, which said SAB had asked it to look into the statements. The move follows SAB's decision to go direct to shareholders after Foster's rejected the UK group's A$4.90-a-share offer.
The panel said SAB had claimed that there was "no reasonable basis for several forward-looking statements" in the results presentation about the Australian company's financial performance. It added that "even if there were a reasonable basis, no information is provided to allow shareholders to test the basis of the statements".
The UK group also highlighted the pro forma net debt figure of $877m in the presentation, claiming that it was "inconsistent with Australian Accounting Standards".
The panel said it had made no decision on whether to conduct proceedings, nor did it comment on the merits of SAB's claims.
Daniel Nelson, an analyst at Constellation Capital Management, said: "My impression is that they [SABMiller] are trying to do everything they can to make sure they do not have to increase their offer price."