"We were helping people find their way, and giving them information about events ... it was really cool being able to showcase New Zealand as well."
Another motivation was that she is a "mad" cricket fan.
That passion is in the blood - the sisters' grandfather, Harold Mendis, was the manager of the Sri Lankan cricket team in 1981.
Ms Mendis, who migrated from Sri Lanka 12 years ago, said her loyalties would be somewhat divided during the tournament.
"I think we mostly go Sri Lanka, but if it's a final with Sri Lanka and New Zealand, then really either way it's going to be fine.
"We have already jumped in and bought tickets for the opening game as soon as they went on sale - that's the one in Christchurch and it's Sri Lanka versus New Zealand."
The head of New Zealand operations for the cup, Therese Walsh, said volunteers were in many ways the face of the tournament for fans, media and officials.
Volunteers wanted
*The ICC Cricket World Cup 2015 will run from February 14 to March 29 next year in venues around New Zealand and Australia.
*New Zealand volunteers 17 years or older are wanted for roles in accreditation, commercial and sponsor servicing, event operations, media and broadcast operations, spectator and fan services, transport, VIP and hospitality.
*Successful candidates will be interviewed next month, and more information can be found at www.cricketworldcup.com.