The ABC is working to understand what caused its flagship show Radio National to go silent after listeners were met with more than an hour of dead air. 

The broadcast went quiet shortly after 8am (AEDT) on the radio, online and on the ABC Listen app.

In a statement, the national broadcaster apologised for the inconvenience and said it is working to resolve the issue.

The ABC is working to understand what is causing its flagship show Radio National to go silent after more than an hour of dead air.  (Paul Jeffers)

“The ABC is aware of an issue which began after 8:00am AEDT this morning and is impacting Radio National and other audio services on broadcast and streaming services including ABC listen,” an ABC spokesperson told 9news.com.au.

“The ABC apologises for any inconvenience caused and we are working to resolve the issue as soon as possible.”

Radio National has partially returned online and on the app.