"She's got an amazing voice and an amazing presence on stage," Ryan said.
Secret Islands Sextet, whose lead musician Jim Langabeer had been involved in the youth jazz competition since the 1960s, was also set to be a highlight, she said.
"There's a story behind each show," Ryan said.
She knew of people travelling from as far as Australia and festival-goers were invited to come in vintage and retro costume.
Tauranga mayor Greg Brownless was set to attend opening night and said he was looking forward to strolling Tauranga's downtown streets and soaking up the festival buzz.
"I think it's part of many people's calendar and they look forward to it each Easter - as I do," he said.
57th National Jazz Festival Tauranga
April 18 to 21
Go to the festival website for the full programme.