Instant messaging application WhatsApp was unavailable in Zimbabwe on Wednesday amid fears that the government was clamping down on social media as the economically and politically troubled Southern African country faced a day of national protest.

ZimNews reported that WhatsApp, which is owned by Facebook, was not working on Zimbabwean networks TelOne, Liquid Telecom Zimbabwe, ZOL Zimbabwe, Telecel and Econet Wireless.

The outage comes as President Robert Mugabe’s government ordered citizens to “go about their normal business” on Wednesday as tensions rose ahead of calls for a national shutdown.

Acting information minister Joseph Made told state-owned ZBC radio’s evening news bulletin on Tuesday: “Government continues to make it clear that all our citizens, in particular our civil servants should continue to go about their normal business across the country.”

Calls for a shutdown have been growing on the back of protests in Harare on Monday and Beitbridge on Friday. There have been threats on social media against schools and businesses that refuse to close their doors.

In one message widely circulated on WhatsApp, threats were made against well-known private schools in Harare as well as against Pick n Pay, which has stores in the capital and other cities.

“Close your businesses tomorrow. This is for the safety of your staff and buildings. Stay away tomorrow and keep the peace please,” read the message, which could not be verified. “Teachers who chose to put their lives at risk … rethink what your heads are requesting of you.”

But minister Joseph Made said: “What is of great concern to government is the falsehoods that are being peddled on social media.”

Anger is growing in Zimbabwe on the back of cash shortages, the imminent introduction of “bond notes”, the police force’s demand for cash at roadblocks and what is widely seen as a ban on imports that will cut off an economic lifeline for many families.

There is also anger over the beatings police dealt out to some protesters on Monday. Said the Crisis in Zimbabwe Coalition, an umbrella grouping of rights organisations: “The state security organs especially the police must forthwith cease to use violence on peaceful protestors… We are in full solidarity with the ordinary citizens.”

While stay-aways have been held several times since 2000, what is different about this one is that it has not been called by any one political party (though it does have the backing of the main opposition Movement for Democratic Change).

In some shops late on Tuesday, shoppers were seen stocking up. Commented @kodzafox: “Zimbabweans outchea buying booze and meat like tomorrow’s a national holiday.”