A man in China has been sentenced to seven years in jail for setting internet equipment ablaze after becoming enraged over a slow connection, authorities have said.

The man, surnamed Lan, was at an internet cafe in southern Guangxi province last June when his frustration with the connection speed spilled over. 

He responded by destroying a public box containing optical fibre network cables, a local court said in a statement on Monday.

The court said the man "used a lighter to set a napkin he had on him on fire, then burned down a telecommunications box at a traffic intersection". 

The fire caused nearly 4,000 households and offices, including a public hospital, to lose internet access for 28 to 50 hours.

"After the incident, public security officials seized Lan's instrument of crime -- a lighter," according to the court in Cenxi, a small mountain city. 

Lan was later hit with a seven-year jail term for "destroying public telecommunications facilities".

The story prompted widespread ridicule on the Chinese internet, with one Weibo user calling the man a "big baby".