An outbreak of scabies in the South Island is causing concern, particularly among tertiary students.

Scabies is a skin condition caused by a parasitic mite and usually produces a very itchy rash.

Te Whatu Ora's confirmed there's been an increase in cases in Canterbury and the West Coast, with a high prevalence in student populations.

Infection Management Clinical Director Dr Sarah Metcalf says other major centres are also seeing lots of cases, and this is part of an international phenomenon.

Christchurch GP Dr Angus Chambers says he's seen the growth first hand over the last few weeks, with many young people seeking medication after their entire flat was infected.

"Students I've spoke to said- oh everyone in my flat's got it. And you know, there's the word out there's an outbreak going round."

Newstalk ZB understands some are struggling to get medication to kill the parasitic mite, with pharmacies out of stock.

Dr Angus Chambers says the pharmacy connected to his clinic in Riccarton has had to ring around in search of stock due to demand.

"It's actually quite problematic because there's quite a lot around, and there's a lack of the usual effective treatment."

There are alternative treatment options, but they come at a cost of up to $40 dollars.

Medication supply company AFT Pharmaceuticals CEO Dr Hartley Atkinson says high demand and post-Covid supply chain problems are delaying delivery of treatments.

"For this particular product, it has been challenging. The use, I understand has gone up almost 50 percent as well."

Dr Hartley Atkinson has spoken to the overseas manufacturer to discuss the seriousness of delays, following a 50 percent rise in demand.