With the Black Caps currently searching for an opener ahead of next year's World Cup, Ryder hit 15 boundaries and five sixes as he raced to triple figures in Lincoln.
Ryder has been overlooked for the national side after a number of behavioural issues but he let his bat do the talking in the one-day match at the Bert Sutcliffe Oval.
Having opened Otago's innings, Ryder immediately set about chasing down Ireland's 248, racing to 43 as early as the third over. His half century came off 16 balls, which would have been good enough to be the third-fastest in list A history but for the teams agreeing to play 12 players a side.
Ryder slowed down slightly in his second 50 before bringing up his ton with a single in the 13th over. Ninety of his runs came from boundaries as the 30-year-old exhibited his power all over the park.
But whether that power will be enough to earn an international call-up remains to be seen. Ryder played the last of his 48 ODIs earlier in the year against India and was surplus to requirements in the current series against South Africa, leaving Jimmy Neesham to join Martin Guptill at the top of the order.
