Spence and her husband Hayden travel to England in two weeks to speak to West Ham officials about ensuring Sneyd's remains move with the club.
"It's a little concerning," Spence, 32, said. "Dad would have been over the moon about the team getting promotion and when the club moves, we want him to go with them.
"We would like for him to be within the sound of the fans singing on the terracings forever."
Sneyd, originally from Margate, Kent, moved to New Zealand when he was 21. He never lost his passion for West Ham - nicknamed The Hammers.
A decision on whether the club will move is expected in the next few weeks. A club spokesman said ashes would be moved only after considerable consultation with families.