The variant was detected on Monday, the Norwegian Institute for Public Health (NIPH) said.
The person infected with the variant travelled from South Africa to Norway in December, the agency said.
Additionally, another four people infected with B117, the more contagious variant first reported in southeastern England, has been detected in a further four people in Norway. The four cases were detected in people who had travelled from the UK to Norway.
Cases of the B117 variant in Norway were first reported in late December.
“Contact tracking teams in the municipalities will now follow up with regard to existing routines with extra testing and closer monitoring of close contacts to reduce the risk of possible further spread,” NIPH head of department Line Vold said in a statement.
A total of 23 cases of the B117 variant from the UK, and one case of the variant from South Africa, have now been detected in Norway.
According to NIPH, both forms appear to be more contagious than the regular variants but do not so far appear to cause more serious illness.
British experts have said that the B117 variant is up to 70 percent more contagious than more common variants of the virus. But it does not appear to be any more deadly, and there is so far no evidence that it is less responsive to vaccines.
“These variants have been detected in several European countries and there is reason to believe the variants may also be found in countries where the genome of the virus is not investigated, meaning mutations are not detected,” Vold said.
“When several countries begin such tests we will get a better insight into the prevalence of this variant,” she added.
One country to have conducted relatively large-scale DNA sequencing on positive Covid-19 swabs, the analysis referred to by Vold, is Norway’s Scandinavian neighbour Denmark.
At least 86 people in Denmark have tested positive for the B117 variant although the actual number could be around nine times higher, according to the country’s infectious disease agency.
Authorities in South Africa issued warnings over the mutation in the country on December 18th having seen a rapid spread in three regions.
The variant in South Africa is not the same as the one detected in the UK, and differences between the two have given rise to questions as to whether the South African variant is even more infectious than the British one.
“There are reasons to be cautious, but it still remains uncertain how large a role these variants are playing in infection rates,” Vold said.
“The normal responses to the epidemic, such as staying at home when sick, testing, tracing and quarantine, social distance and fewer participants at gatherings will also be important limiting factors against this variant,” she added.
“So far, now evidence has been reported that effectiveness of vaccines is affected,” she said.