The Board of Ministers was an agency of the Bajoran Provisional Government. For an individual to approach Benjamin Sisko directly, they must request permission through the Board of Ministers, a process that can take months to process.
Doctor Mora Pol circumvented this process in 2370 by contacting Odo in person, who he had, in turn, ask for Sisko's permission to travel to the Gamma Quadrant to investigate the Changeling's origin. (DS9: "The Alternate")