A raft of Australian institutions – including major banks, media outlets and an airline – have reported being hit by a mass IT outage.

Jetstar has been crippled at Sydney airport, supermarkets are experiencing checkout chaos, and broadcast networks have been left scrambling on air as autocue and graphics failed.

Hours before Australia was severely affected, a handful of airlines in the US also reported having to ground planes due to IT issues.

The cause of the outage is unclear, but many of those affected have linked it to Microsoft PC operating systems.