South African nationals have until now been admitted to Britain without visas.
Jacqui Smith told parliament on Monday that the two countries, along with Bolivia, Lesotho and Swaziland, had failed to provide sufficient guarantees in terms of security and immigration. Citizens from those countries traveling to the U.K. will initially be restricted to six-month visas, and will have to provide fingerprints during the application process.
The changes will come into full effect by the middle of this year, but first-time South African visitors to the U.K. will have to apply for visas as of March 3.
The new rules are "part of the biggest ever changes to strengthen Britain's border security through stronger overseas checks, tougher border checks and tough enforcement action," Smith said.
The decision on South Africa follows intelligence reports that the country has been used as a transit country for Islamic extremists entering the U.K. Over 400,000 South Africans legally visit the U.K. each year.
