The Malaysian Government has blocked internet coverage of a large anti-government rally planned for the weekend and threatened to send in the army to restore order as it scrambles to contain what is likely to be a massive public show of disapproval in the government of Prime Minister Najib Razak.

Malaysia's biggest civil society group, Bersih, is hoping that hundreds of thousands of people will take to the streets of Malaysian cities this weekend to protest against the political and financial scandals that have rocked Malaysia.

Bershih 4.0 is shaping up to be a huge rally in Kuala Lumpur on August 29-30, with satellite rallies in Kuching, the capital of the state of Sarawak, and Kota Kinabalu, the capital of Sabah. Starting at 2pm local time on Saturday, the rally will run for 34 hours with the aim of shutting down the capital, Kuala Lumpur, ahead of Merdeka Day, Malaysia's national holiday marking independence from Britain.

Bersih, which means 'clean' in Malay and refers to the Coalition of Free and Fair Elections, is an umbrella group of 84 NGOs and civil society groups. They are calling for institutional reforms and for the resignation of Prime Minister Najib Razak. Officially, Bersih 4 has several key demands: clean elections; clean government; the right to dissent; strengthening parliamentary democracy and saving the economy.

Between 2007 and 2012, Bersih organised three street protests in the capital. Organisers say 300,000 people attended in the last rally in 2012. It ended with street scuffles and police responding with water cannons and tear gas. Hundreds of protesters were arrested.

Malaysians have been transfixed by the unfolding political and financial scandals besetting Prime Minister Najib Razak and his inner circle for the past several months. The planned protest comes amid allegations of Najib's mismanagement of the debt-laden 1 Malaysia Development fund (1MDB) and allegations of impropriety over a RM2.6 billion (US$700 million) 'donation' deposited into Najib's personal bank accounts.

The sacking of the country's most senior lawmaker, Attorney General Abdul Gani Patail, and other key ministers who spoke out about the 1MDB scandal has further incensed many Malaysians.

The political fallout is also having a financial impact. The Malaysian currency, the Ringgit, has shed 20% in value over a year as the oil-exporting country suffers from a prolonged oil price rout and escalating political scandals.

Malaysian authorities, worried that the impetus is building towards an embarrassing public spectacle, are cracking down in the hope of preventing mass participation. Malaysian police have declared the rally in Kuala Lumpur illegal, stating that proper permissions for routes and venues were not submitted for approval. The rally in Sabah has also been deemed illegal. Lawyers disagree, and the most prominent human rights legal group, Lawyers for Liberty, has posted short instructional films on Twitter to explain legal issues surrounding the protest and to offer advice for dealing with arrest and interrogation (see above). 

On Thursday, in a worrying sign for freedom of speech, Malaysia's Communications and Multimedia Commission (MCMC) banned all websites 'that promote, spread information or encourage the public to join the Bersih 4.0 demonstration.' Public universities have also warned students not to attend the rallies, saying that students could be expelled or suspended if they attend. Also on Thursday, the Malaysian military warned it will intervene if a state of emergency is declared. While this appears to be a scare tactic aimed at persuading people to stay at home, the government nonetheless seems intent on doing everything it its power to prevent a mass demonstration.

Despite these efforts, large crowds are expected. A sophisticated social media campaign has been in action for weeks and the opposition-friendly media has promoted the rallies. The hashtag #Bersih4 is trending on Twitter in Malaysia. 

If the number of protesters is large, the rallies will be seen as a public vote of no confidence in Najib. However, if the ultimate aim is to unseat him, the protests seem likely to fail. Malaysian politics has shown time and time again that the prime minister does not need the people's support to survive.

Najib seems determined to stay, perhaps worried about the legal action he could face if he stepped down. He looks increasingly likely to lead his ruling Barisan Nasional coalition into the next general election in 2017. Perhaps the best result that the Bersih 4.0 rally can hope for is to instill in the ruling UMNO leadership a sense that the Prime Minister is no longer electable. But the UMNO party leadership conference, the forum that could vote him out as leader, has been delayed for 18 months.