Zimbabwe's finance minister expressed concern on Wednesday that a US withdrawal from the World Health Organization (WHO) will lead to aid cuts to countries such as his that are most affected by HIV/AIDS.

President Donald Trump signed an executive order on the US withdrawal after his inauguration to a second term on Monday.

Warning that a US withdrawal could signal cuts in health aid to countries such as Zimbabwe, Finance Minister Mthuli Ncube said: "Any country with an HIV/AIDS challenge will be impacted."

"This is a concern, a fear we are expressing," Ncube told an online briefing from the Swiss resort of Davos, where was attending the World Economic Forum.

Zimbabwe receives over $200-million annually from the US President's Emergency Plan for AIDS Relief (PEPFAR), and the US government has given Zimbabwe over $1.7-billion since 2006 to strengthen health systems and support people living with HIV, according the US embassy in Harare.

PEPFAR contributes nearly $90-million a year to support salaries and incentives for healthcare workers in Zimbabwe, in addition to funding HIV and viral load testing, prevention, cervical cancer screening and tuberculosis treatment.

Zimbabwe is struggling to fund its public health system, and the government introduced a sugar tax on beverages last year to help raise funds for cancer treatment. Another tax on fast foods was introduced this year.

"We need to scale up our funding for health. The earmarked taxes should be directed towards health as we build our capacity to fill the gap should any funding recede," Ncube said.