The Commonwealth Bank's chief executive has told the banking royal commission some mortgage brokers are earning millions of dollars a year thanks to rising property prices.

Matt Comyn said Sydney-based brokers had seen their earnings double, with the top 200 taking home about $2.5 million a year. He told the commission he wanted to end broker commissions, but could not because the bank would lose customers to its rivals.

Mr Comyn is the first boss to take the stand as the commission questions the culture and governance of Australia's financial institutions.

See how the day's evidence unfolded on the blog.