Shares in Ronin, which has specialized in office development in Australia and New Zealand and runs a property trust, slipped 1.6% before trading was stopped, valuing its equity at A$1.26 billion ($900 million). The shares had risen 3.3% during the week on speculation that it would become a takeover target.

Multiplex shares edged up 0.8% at A$3.67 before trading was halted, putting its market value at A$2 billion ($1.4 billion). The company, which is building London's Wembley Stadium, says it will submit the merger proposal by next Tuesday.

A takeover will enable Multiplex to access steady income from Ronin's property investment unit, which through a joint venture with AMP Capital NZ runs New Zealand-listed trust ANZO. It will boost the proportion of Multiplex's income from property investment to more than 50% and make it eligible for the listed property trust sector.