However, no details of the sponsorship are being released.
Project Excel director Karin Bowen, who is a project manager for the festival, said the changed role of Contact from a sponsor to a partner meant it had an interest in the future of the festival, rather than just providing financial contributions.
"They are more like a development manager; they want to see the festival grow and to see the community benefit from it.
They will be involved in partnering the process all the way through," she said.
Contact hydro generation manager Graham Quinn said the company's increased involvement meant it would sponsor the festival's live concert in Pioneer Park, which was scheduled for the opening night on September 27.
"We will also sponsor the grand street procession and will provide a set of prizes to encourage schools to participate in creating floats for the procession," Mr Quinn said.
Festival committee chairman Steve Battrick said with Contact a principal partner, the festival had the potential to grow in future years.
"We are extremely grateful.
If there were any doubts as to the festival continuing beyond its 50th year, these have been well and truly allayed," he said.
