Wallenberg, who served as special envoy at the Swedish embassy in Budapest from 1944 to 1945, saved the lives of tens of thousands of people who would have otherwise dies in the Holocaust.
Writing in the debate pages of newspaper Dagens Nyheter, the Liberal Party minister says Wallenberg serves as a symbol of solidarity, transparency and tolerance in a time when extreme-right groups are gaining ground in Europe.
"If Sweden does not commemorate Wallenberg for future generations - who will then attend to his memory?" Ohlsson asks.
Several memorial services will take place in Sweden Saturday, and in the rest of the world.
The city of Berlin will reveal a new monument, and a segment of 13th Avenue in Brooklyn, New York, will be renamed Raoul Wallenberg Avenue, the news agency TT reports.
When the Soviet Red Army moved into Hungary in early 1945, they arrested Wallenberg as a spy, and sent him back to the Soviet Union.
He was reported to have died from a heart attack two years later, but for decades reports surfaced from prisoners who said they might have seen him alive.