The head of the Commonwealth Bank of Australia's asset management arm says the group will increasingly lean on the bank's balance sheet to pursue infrastructure assets, as it contemplates injecting more than $1 billion into a consortium bid for British airports operator BAA.

If the deal proceeds, it will almost double the value of the infrastructure assets managed by Colonial First State Global Asset Management's infrastructure division. The investment would be spun off into a separate fund offered to investors in a business model similar to that used by Macquarie Bank and Babcock & Brown, which have successfully listed several funds after acquiring large offshore assets.