(Adds quotes from regulator)
SYDNEY, July 19 (Reuters) - Australia's four biggest banks will be required to have Tier 1 capital ratios of 10.5 percent by January 2020, the country's prudential regulator said on Wednesday.
The Australian Prudential (LON:PRU) Regulation Authority (APRA) said in a statement that the increase in capital, which is about 100 basis points above December 2016 levels, would allow the banks to meet a benchmark of being "unquestionably strong".
"Capital levels that are unquestionably strong will undoubtedly equip the Australian banking sector to better handle adversity in the future and reduce the need for public sector support," APRA Chairman Wayne Byres said in a statement.
Australia's four biggest banks include Commonwealth Bank of Australia CBA.AX , Westpac Banking Corp WBC.AX , Australia and New Zealand Banking Group ANZ.AX and National Australia Bank NAB.AX .
Australia has a highly concentrated banking system, with the "Big Four" controlling around 80 percent of lending.