Only legal residents or nationals of Spain and the neighbouring micro-state of Andorra are currently allowed in on flights from these countries.
The restriction on arrivals from Britain was imposed at the end of December while the ban on arrivals from Brazil and South Africa came into effect on February 3rd.
Spain's cabinet agreed on Tuesday to extend these entry restrictions for another two weeks, Health Minister Carolina Darias told a news conference.
This is the fourth time that Spain has extended its restrictions on arrivals from Britain.
Other European nations have also imposed curbs on arrivals from the three nations due to fears that new variants may spread more easily or contain mutations that allow the virus to evade the effects of vaccines.
Spain on Friday confirmed the first case of the Brazilian variant while at least two cases of the South African variant and 479 cases of the British one have already been detected.
Officials predict the British variant could become the dominant strain in Spain by March.
Spain has been hard-hit by the pandemic recording over 62,000 deaths from nearly three million cases so far.