The Change.org petition aims to stop the prosecution relating to the pilots and Bay of Plenty MP Todd Muller has publicly thrown his support behind it.
Muller did not think it was right to "throw the [pilots] under the bus" and take them to court to find out who was culpable and who was not.
"They went to save people. That should be acknowledged."
Former Tauranga mayor Greg Brownless also backed the petition.
"I think it is mean-spirited to prosecute the very people who did put their lives on the line voluntarily."
Brownless said the charges were a "kick in the stomach".
"I just feel ashamed for what has happened. It's a gross injustice."
Rotorua mayor Steve Chadwick would not comment on the petition or the industry's response to the WorkSafe investigation without knowing more details.
WorkSafe NZ earlier said none of the charges against the 13 parties related to the rescue or recovery efforts.
The investigation centred solely on the health and safety measures in place prior to the eruption, the organisation said.
It said in a statement that post-eruption actions would be subject to other proceedings including a coronial inquest.
The statement said WorkSafe did not prevent the rescue and recovery operation.
Rotorua National MP Todd McClay said he was not aware of the charges or the background circumstances to them so it was hard to comment on a petition.
"Worksafe has charged a lot of people and while some people had outed themselves, it was still unclear who all the parties are, their charges and why they have been charged."
McClay said there were a lot of adventure tourism operations in the region and the risks need to be considered so visitors and tourists had the assurance they were safe.
He said if the charges against the pilots were in relation to saving people he could understand the public being disappointed.
Whakatāne mayor Judy Turner did not want to comment.
