Both players spent last season away from Birmingham City.
Stewart spent last season borrowed by St Mirren's league rivals Aberdeen and it is claimed that he is 'up for grabs' again this summer, with the same said to go for Brock-Madsen, who has had temporary spells with PEC Zwolle and KS Crakovia since 2016.
A number of clubs are keen on Stewart, however, according to the Scottish Sun, which adds that his wages are proving a stumbling block for St Mirren.
Birmingham are said to be battling to lift a transfer embargo imposed on them by the English Football League, although offloading fringe players such as Stewart and Brock-Madsen is unlikely to have a major impact on the Blues' situation.
Birmingham fans - which others would you like to see leave St Andrew's?