The Financial Post reports in its Saturday edition that Brookfield Asset Management has shelved a $6.5-billion (U.S.) buyout agreement with Australian port and rail giant Asciano and said it will launch a formal takeover offer instead. A Reuters dispatch to the Post says Brookfield's move threatens a rival proposal and raising the antitrust regulator's role in deciding the outcome. Since Brookfield and Asciano agreed to a buyout in August, local port competitor Qube Holdings has bought one-fifth of the target and vowed to oppose a Brookfield takeover in favour of its own proposal to split the target's assets between itself and global investment partners. The Australian Competition and Consumer Commission has also suggested it might stop Brookfield buying Asciano since the Canadian suitor already owns some of the railways Asciano's trains run on. It will make a final ruling on Dec. 17. On Friday, Brookfield fought back by buying its own one-fifth share of Asciano, adding it would delay the agreed buyout and launch a formal takeover instead, meaning it needs only 50.1-per-cent shareholder approval, rather than 75 per cent. That effectively kills Qube's chances of using its stake to help block the deal.