Singapore's ARA Asset Management has increased its offer for shares in Cromwell Property Group by 4.4 per cent as it seeks to win over mum and dad retail security holders and lift its stake through on-market purchases in Brisbane-based Cromwell to 26.7 per cent.

But the move by ARA, which has a 24.1 per cent stake, to lift its offer to 92¢ a share from 88.1¢ also raises the price it is willing to pay for an additional 29 per cent stake it is trying to acquire in its long-running battle with Cromwell, as it seeks to get seats on the board and influence the strategy of a company it says is flawed.