Social media anger from Chinese nationalists over a Thai internet model's comments on the coronavirus has set off a storm, uniting pro-democracy campaigners against pro-Beijing cyberwarriors, with insults and mocking memes flying.

The quarrel, which has seen Southeast Asian internet users join forces with those in Taiwan and Hong Kong, has highlighted old tensions between China and its smaller neighbors, with those fanned by the emergence of the new coronavirus.

Political analysts and activists said the online row, which started at the weekend, was unique in volume and regional spread at a time when ever more of life has been forced online.