Broadcasters will need to have permission to use Cantonese on television, radio and in online footage from March, according to an order posted on the Guangdong provincial government website.
It comes just over a year after the government proposed switching prime-time programming on Guangdong TV's main channels from Cantonese to Putonghua. The proposal was later postponed when it triggered a series of mass demonstrations by furious Cantonese speakers.
The new order was passed by Guangdong authorities on December 1 and signed by acting governor Zhu Xiaodan last Monday. It will come into effect on March 1.
According to the order, Putonghua should be the main language for broadcasts, programmes and interviews on television, radio and in internet videos. Central or provincial radio, film and television administrations must approve any use of dialects, the order said.
Penalties would apply to people in charge of the programmes that contravened the rules.
Although the order is similar to existing regulations at a national level, the release of such rules by the Guangdong government has generated unease.
'Cantonese is the most ancient language in China. It is not a dialect - hundreds of thousands of people all over the world use Cantonese. I feel very uncomfortable about [the change],' a Cantonese-language radio host said
An activist behind last year's Cantonese-language campaign said: 'This will strangle the local traditional culture.'
A Cantonese programme host at Guangzhou TV said the order would not seriously affect his programme because the stations had always been under government control and the existing Cantonese programmes were unlikely to be affected. 'But what is most affected are the feelings of ordinary people. People definitely feel their language and culture are being suppressed,' the host said.