A total of ten fires were of a "serious nature", a Swedish Civil Contingencies Agency (MSB) spokesman told AFP.
Eight helicopters were being used to fight blazes in the south that were reported to be under control on Wednesday afternoon.
"They have them under control," MSB press secretary Marcus Årskog told Swedish news agency TT.
The most severe covered 300 hectares and broke out in Hässleholm municipality in southern Sweden, forcing 49 people to evacuate.
Last year a historically hot summer set a total of 25,000 hectares of forest ablaze in Sweden, almost ten times the yearly average, according to a government study.
MSB said the exact cause of the spring fires was not known but believed them to be the result of human activity, either from barbecues or forestry machines.
The sunny and warm spring weather had also made the fire risk unusually high for the season.
"The next few days look really bad," Anneli Bergholm Söder, head of operations at MSB, told a press conference on Wednesday, adding that more humid weather was expected for the weekend which would likely improve the situation.
MSB also said Sweden was much better equipped to deal with the fires this year, having taking a number of steps to improve its capacity to respond.
Among the measures were a system with different private contractors, making up to 30 helicopters available for water bombing.
However, Brandmännens riksförbund, a union representing firefighters in Sweden, said they were hampered by a lack of workers, and that around 2,800 full and part-time firefighters were needed for them to remain fully staffed over the summer, TT reported.
A forest fire in Sokndal on Tuesday evening. Photo: Tor Erik Schrøder/NTB scanpix/TT
In neighbouring Norway, hundreds of hectares of forest were also destroyed by fires between Tuesday and Wednesday.
Local authorities announced they had largely contained the most threatening fire, which covered some 700 hectares in Norway's south-west around Sokndal.
No injuries were reported. Some 148 homes were evacuated but all residents returned by Wednesday afternoon after 150 firefighters and six helicopters were mobilized.
Norwegian Minister of Public Safety Ingvil Smines Tybring-Gjedde told TV2 she had "learned from the lessons" of the 2018 fires and helicopters and staff would be on constant alert during the summer.