Abstract We elaborate the generalizations of the approach to gauge-invariant deformations of the gauge theories developed in our previous work (Buchbinder and Lavrov in JHEP 06:097, 2021). In the given paper we construct the exact transformations defying the gauge-invariant deformed theory on the base of initial gauge theory with irreducible open gauge algebra. Like in [1], for the theories with open gauge algebras these transformations are the shifts of the initial gauge fields $$A \rightarrow A+h(A)$$ A → A + h ( A ) , with the help of the arbitrary and in general non-local functions h(A). The results are applied to study the quantum aspects of the deformed theories. We derive the exact relation between the quantum effective actions for t...