The Swedish news agency TT Monday reported on allegations the queen's father, Walther Sommerlath, who died in 1990, joined the Nazi party in 1934.
Silvia said her father was never politically active and Sommerlath continued to deny the allegations until his death.
A documentary last year alleged Sommerlath took over a factory owned by a Jew in 1939. Sommerlath denied those allegations as well.
"The difficulty is that this happened over 70 years ago, there has been a World War in between and so much is incomplete," royal spokesman royal Bertil Ternert said. "However the queen would still like to make an effort to produce as clear picture as is possible."