Australia all-rounder Mitchell Marsh said Tuesday "everyone calls me Shaun" after he was spotted wearing his brother's number on his cap at the Cricket World Cup.

"I've asked a couple of times to get my number on my cap and they keep sending me Shaun's number," said 32-year-old Mitchell.

"So, everyone here calls me Shaun anyway, so it works out well!"

The left-handed Shaun, 40, announced his retirement from first-class and ODI cricket in March after a eight-year international career including 38 Tests and 73 ODIs.

His ODI cap number was 165 while Mitchell should have 190 emblazoned on the side of his hat. That would correspond with him being the 190th Australian to be named into the team.

Mitchell has been in fine form at the World Cup and goes into Wednesday's game with the Netherlands in New Delhi on the back of making 121 in a 259-run opening partnership with David Warner against Pakistan.

Mitchell's father Geoff was also an opener, enjoying many marathon stands with David Boon.

"Yeah, that partnership (between Geoff and Boon) would have taken four days to get that many," joked Mitchell.