HO CHI MINH CITY (AFP) - A critical blog post could land you in jail in communist Vietnam, but a satirical image of Cinderella which mocks the ruling elite? Likely to slip past the censors.

The country's roughly 33 million Internet users, armed only with laptops and a sense of humour, are driving broader social change in the authoritarian nation than scores of imprisoned firebrand bloggers, experts say.

From their calls for the health minister to resign - a cause so popular that a state-run newspaper briefly took up the campaign - to amusing attacks on ham-fisted censorship, Vietnam's ever-growing ranks of Internet users are finding their voice.

"The kids creating and sharing these images don't think of it as activism, for the most part. They're not necessarily campaigning for anything. They're just making jokes," said Patrick Sharbaugh, a digital culture researcher who has worked in Vietnam.

"An ersatz civil society is emerging out of this," he said.

Criticised over a spate of baby deaths after routine vaccinations, Health Minister Nguyen Thi Kim Tien was the target of hundreds of memes including unflattering photos of her with the words: "Without me, how would funeral services thrive".

In a one-party communist country where public loudspeaker systems still broadcast official news twice daily and all media are state-run, the space the Internet creates is important.

At the forefront of the revolution is the "meme" - an idea or piece of content, similar to viral content, but changed or remixed as it spreads.

While still not as widely used in Vietnam as in the United States or China, "there's a lot of growth to come," said Ben Valentine, an American writer for The Civil Beat website which examines memes and viral media.

"It's very exciting," he added. "While censorship is extremely harmful socially, it can breed intense creativity."