New Zealand captain Brendon McCullum broke the world record for the fastest test century held jointly by his idol Viv Richards on Saturday without ever being aware he was about to make cricket history.

McCullum, 34, who is playing his 101st and final test, struck the ball with brutal brilliance to reach his 12th century from 54 deliveries on the opening day of the second test against Australia at Hagley Oval.

West Indian Richards set the previous record of 56 balls against England in Antigua in 1986 and the mark was then equalled by Pakistan's Misbah-ul-Haq against Australia in Abu Dhabi in 2014.