The United Nations said the promise of economic and social development, democracy, justice and peace was being threatened by acute resource constraints on Sudan's transitional government.
Sudan risks being plunged into a humanitarian disaster by Covid-19 unless sanctions are lifted and donors provide financial support, the UN rights chief said on Tuesday.
Without international backing, the country's transition towards peace and stability could swing into reverse, Michelle Bachelet said in a statement.
A year has passed since president Omar al Bashir was ousted by the army on April 11, 2019, following months of nationwide protests.
Prime Minister Abdalla Hamdok took power as head of a transitional government sworn in last September, but Sudan's economy remains in deep crisis.
Bachelet said the promise of economic and social development, democracy, justice and peace was being threatened by acute resource constraints on the transitional government.
She said they were being exacerbated by ongoing unilateral sanctions, the failure of international institutions to provide debt-relief, and a deficit of international support.
"The tipping point could be Covid-19," Bachelet warned.
"The health system is simply not equipped to handle an outbreak on the scale we have seen elsewhere in the world. There is only one way to prevent a humanitarian disaster, and that is for the donors to step up and extend a helping hand to Sudan."
Khartoum remains on a US blacklist as a state sponsor of terrorism, stifling investment.
It is for instance not eligible to access the emergency financing set up by the World Bank and the International Monetary Fund to help countries combat the Covid-19 pandemic.
Households continue to suffer from frequent power cuts and most Sudanese still queue up for hours to buy staple foods or to fill their cars with petrol.
In response to the novel coronavirus pandemic, the government announced a 24-hour curfew for three weeks from April 18 across Khartoum state.
Sudan has seen 237 confirmed cases and 21 deaths, according to the latest World Health Organization figures.
"The only way Sudan will ever be able to break out of this cycle of poverty and desperation is to be freed from the impediments of sanctions imposed at the time of the previous government," said Bachelet.
The former Chilean president said that without addressing the economic and social grievances that sparked the ousting of Bashir, "Sudan's successful transition to achieving a durable peace remains distant."