Mark Steinberg of the IMG agency said that neither he nor Woods gave permission to use the golfer's likeness.
'The most disappointing thing is that a political position is stated and that's just wrong, so outrageously wrong,' Steinberg is quoted as saying in a Detroit Free Press story published Saturday.
Proposal 2 asks voters to let the state borrow $1 billion to fight water pollution and beach closings. Communities could then get state loans to improve their sewer systems.
The billboards -- located in Lansing, Grand Rapids, Battle Creek, Flint, Kalamazoo and Detroit -- feature a drawing of a golf-club-toting Woods with the words 'water hazard' in red. They show Woods spitting out murky, brown Michigan water and saying he doesn't feel 'up to par.'