Australia's major banks will be forced to share more detailed credit data about millions of customers, a move the government says will result in better deals on loans and greater competition in banking.

Treasurer Scott Morrison will on Thursday announce plans to mandate a system known as "comprehensive credit reporting" from the middle of next year, and the new requirements will apply to the Commonwealth Bank, ANZ Bank, Westpac and National Australia Bank.

The credit reporting regime, which has been voluntary for the past few years, will mean the major banks must give credit bureaux more detailed data about their customers' financial behaviour.

While banks were heading in this direction anyway, Mr Morrison will argue that progress has been slow, and it was clear the banks would not meet the government's targets in this area.