The American singer dressed in theme for Bright with a fluorescent yellow dress, blue sneakers and a high ponytail on Wednesday.

The California girl came to bring cheer to those impacted in Victoria's recent bushfires, pulling out all the stops in the tourist town.

"The point of coming out is just a message of gratitude and unity," she told reporters.

"No matter where you are suffering in the world, we are all one. We can support each other in our own way."

Perry wanted to show her support in person, after seeing the "very apocalyptic" fire scenes from California.

Thousands of Victorians turned out to see Perry, as a way to celebrate coming through the fire season.

"This is exactly what my hometown looks and feels like. (But) We don't have any pies in the USA," Perry told fans while on stage.

"Congratulations for coming out on the other side."

Along with these fighting words, Perry hopes to spark a passion for people across the globe to take action on climate.

"It's another loud shout from Mother Nature, saying okay hold my beer," she told reporters.

"Unfortunately, I think a lot of these types of things are going to continue to happen unless we take drastic measures into effect."

Her eyes were on the emergency services personnel who gave their all in the disaster.

Volunteer firefighter Dara Pilly, 21, was among the emergency workers called up on stage before Perry sang Happy Birthday to her and a forest fire management worker.

"It is not everyday that a person like Katy Perry comes to a small town like this ... everyone is so lucky," Ms Pilly told AAP.

"Definitely not your average 21st birthday getting to do something like this."

Ms Pilly fought the Corryong fire alongside her parents and siblings, but was now just happy to still be standing - with international hit-maker Perry.

After about a dozen tracks, the concert finished with a bang as Perry sang her 2010 song Firework.

While Bright wasn't burned in the fires, it has been been financially devastated as tourists turned away, losing an estimated $90 million in tourist income.

In town, a banner of Perry's lyrics hangs outside Bright Activities Novelties and Games to urge victims to keep dancing to and celebrate.

"I don't think you can word it any better than she did - dancing through the fires. That is exactly what we did, we've experienced the fires and now we want to dance and celebrate," owner Roshelle Harrison told AAP, after her girls and friends made the sign.

"Things will pick up and we will be back on track but we will never make up for what we lost."

Her business took an 80 per cent hit in January but is almost back to normal - with hope for Easter and the snow season ahead.

Australian Associated Press