National Australia Bank's venture capital arm is buying into real estate investment platform BrickX, as the bank eyes the potential of a system that allows aspiring first home buyers to purchase small stakes in properties.

The NAB Ventures fund is joining Westpac's Reinventure fund as an investor in BrickX, bringing to a close a wider funding round that will inject a total of $9 million into the platform.

Marc Burman, 20, says investing through BrickX is a stepping stone to one day buying an entire property. Credit:Janie Barrett

NAB did not reveal the size of its stake, but it will have a board seat, as will Westpac, which announced its investment last year.

NAB Ventures managing director Todd Forest said the key factor in the deal was the bank's desire to deal with the high cost of housing for younger people, especially millenials.