"The thing is, [Greg] has terminal cancer. He was going to take his daughter, who is obsessed with Hi-5, to the show and now the whole thing is just not going to happen," she said. "We thought he'd get to do this with her.
"She's only 2, but she's obsessed with this show - she has all the dolls and everything."
Mrs O'Donoghue said 11 family members had planned to head to Wellington for a five-day holiday centred on the Hi-5 show.
She estimated she had spent almost $4800 on flights, accommodation and tickets for the performance of the Australian band, which was launched in 1998 to entertain children aged 2 to 8 with music, movement, problem solving and play.
She said the family group - which included five adults, three teenagers and three kids aged 18 months, 2 and 3 - would still go to Wellington this month, but wouldn't be able to make it back for the October show.
A spokeswoman for Hi-5 promoter Live Nation said ticket-holders would be able to get refunds for the tour, which had been postponed "due to a change in international filming commitments".