Spain has detected its second known case of infection with the South African coronavirus variant in the northeastern region of Catalonia, officials said on Wednesday, a day after the government decided to restrict air travel with Brazil and South Africa.

Catalonia's public health secretary Josep Maria Argimon said this second detected case, along with the expansion of the British variant, were "not good news" amid efforts to tackle the pandemic.

Meanwhile in Madrid, authorities warned that cases of the highly contagious British variant were growing exponentially and it would likely become the dominant strain across the region in a matter of weeks.

"That means a change to the rules of the game and to the approach we have been taking over the last few months," deputy regional leader Ignacio Aguado told a news conference.

Last week, the national health ministry said it had confirmed 267 cases of the British variant across Spain but it was studying many more samples.