Sudanese activists are calling for mass demonstrations on Friday as the government intensifies its crackdown on anti-government protests that have now entered their second week.

Popular protests sparked by austerity measures aimed at reducing the government's $2.4bn budget deficit have spread from the capital Khartoum to other areas of the country, transcending mere student activism to include calls for an end of the 23-year-old regime of President Omar Al-Bashir.

"We’re calling on the ruling National Congress Party (NCP) to step down," Dalia Al-Haj Omar, spokeswoman for the Girifna opposition movement, told Ahram Online via email.

The Friday demonstrations have been dubbed "The Fiday of Elbow-licking" to mock the NCP’s vice chairman, Nafie Ali Nafie, who famously used the sudanese idiom "only if you can lick your elbows" (an Arabic equivalent to the popular American saying when pigs fly) to dismiss the possibility of an Arab Spring style uprising against the regime.

"Our demands are based on justice, peace and freedom."

Activists have listed 15 demands for Friday's protest, including the replacement of the current NCP-run government with a transitional one representative of all of Sudan's geographical regions, civil society, youth and women; and fresh national elections within two years.

Demands also include the elimination of all 'public order' laws and laws restricting freedoms; the establishment of price controls to stop runaway inflation on basic commodities; the release of all political prisoners; guarantees of political and press freedoms; and an end to the practice of using religion as a means of cowing political opponents.

Security forces have used teargas, rubber bullets, batons and live ammunition in an effort to suppress the growing tide of demonstrations that have swept the country in the past two weeks. Scenes in Khartoum last week recalled recent events in Egypt, Tunisia and Libya, featuring the liberal use of teargas, burning tyres and rock-strewn streets.

Chanting the slogan made famous by the Arab Spring – 'The people want the fall of the regime' – men, women and children in some areas fought back against police who bombarded them with teargas and rubber bullets by throwing rocks and blocking roads.

The demonstrations first began when the government hiked transport and fuel prices, raised taxes and devalued the currency in an effort to offset the loss of roughly three quarters of the nation’s oil revenue following the secession of South Sudan last year.

Al-Bashir played down the demonstrations on Sunday as the work of "agitators" as the government insisted it would press ahead with its planned spending cuts.

"We've already witnessed the Arab Spring a number of times," the president declared in a televised speech last week. "When the Sudanese people revolt, they all come out. Those who are burning tyres now are only a few agitators."

Press freedom advocates have described an intensifying clampdown on critical voices in recent weeks, including the seizure of newspapers.

Human Rights Watch on Wednesday urged Sudanese authorities to end the crackdown on the anti-government protests, which have led to the arrest and detention of reporters and protesters. "Authorities should end the violence immediately and respect the people's right to protest peacefully," HRW declared in a statement.

Sudanese expatriate communities around the world, meanwhile, are organising a day of solidarity with the 'Sudanese revolution' on Saturday, according to the Girifna opposition movement's official website. They are expected to assemble in various cities, including London, Dublin, New York City, Washington, Toronto and Paris.