One person was killed and at least two injured by two near-simultaneous blasts in a Japanese park today, the local fire department said.



The explosions occurred at a park in Utsunomiya, some 100 kilometres north of Tokyo, shortly after 11:30 am (1.30pm AEDT), a fire department spokesman said.



It was not immediately clear what caused the blasts.



"One person was found dead," the fire department spokesman said, without elaborating further.



Public broadcaster NHK said a body badly damaged in the blast was found at a bicycle parking space for the park.



"The sex and ages of the three are not known yet," another local fire department official said, adding one blast hit a car parking lot for the park.



NHK footage showed a car completely charred, as fire fighters poured water on it.



A man told NHK that he "smelled gunpowder in the area" after the explosions.