Sum 41 have cancelled their Australian tour as Deryck Whibley battles pneumonia.

The 'In Too Deep' pop punk legends are currently on their farewell tour, but their Aussie leg - including a co-headline slot at Good Things Festival - has been scrapped after advice from doctors.

As reported by Billboard, in a since-deleted statement the band wrote on Facebook: "It is with deep sadness and regret that we announce our 2024 Australian tour is unable to proceed.

"We were beyond excited to deliver this tour from December 4 - December 12, and connect with our Aussie fans once more.

"Now that we're here though, and under the guidance and direction of multiple Australian doctors, it's clear that Deryck is too unwell to perform.

"We understand and appreciate your disappointment - we're gutted too."

It's said the 'Fat Lip' hitmakers still encouraged their fans to attend this weekend's festival.

They added: "The good news is Good Things Festival is still going ahead in Melbourne, Sydney and Brisbane this weekend with an incredible line-up of local and international acts.

"We can't be there, but get along for us and have the best time."

Meanwhile, the festival - which will see Korn headlining with Jet, Billy Corgan, Violent Femmes and others on the bill - has sent "well wishes" to Deryck.

They said in a statement: "Sum 41 are gutted they can't perform, and we fully understand and appreciate fans' disappointment.

"Deryck's health and wellbeing is the focus and priority though, and we hope you will join us in sending him well wishes for his recovery."

revealed earlier last year they would be splitting after the release of their eighth album 'Heaven :x: Hell' and a farewell world tour.

Announcing their plans to disband, the group wrote at the time: "Being in Sum 41 since 1996 brought us some of the best moments of our lives. We are forever grateful to our fans both old and new, who have supported us in every way.

"It is hard to articulate the love and respect we have for all of you and we wanted you to hear this from us first."