Speaking at a press club event in Munich, the Bayern boss shot down speculation the club's star wingers could be headed out the door.
Olise, who impressed in France's run to the World Cup semi-finals, has been linked with Real Madrid for weeks, while some have speculated Diaz may be set for a big-money move to Saudi Arabia.
"It's surprising to see what gets said when you know the truth yourself; it's interesting," the 58-year-old said.
Dreesen said Olise would "obviously" be at Bayern next season and said he had received "zero" calls from Real "and not a single letter, fax or email either."
Asked about Diaz, Dreesen said: "the same applies there: no calls, nothing else.
"We'd be foolish to do so. We have such a good team; let them play and score goals."
Both Diaz, who joined in 2025, and 2024-arrival Olise are at Bayern on deals which expire in 2029.
The CEO was confident England captain Harry Kane would extend his contract at the club, which is set to expire at the end of next season.
"There's a strong desire (to extend) on both sides. We'll have to see how that desire aligns."
Kane, who turned 33 on Tuesday, scored 61 goals and laid on seven assists in 51 matches in all competitions for Bayern last season.
