The paper evaluates the relative effect of deterrence, prevention, curative and commitment policy measures on the size of undeclared work in a real business cycle model with undeclared work, tax evasion and search frictions in the labour market. A numerical application of the model to the European economy shows that all these approaches reduce the undeclared share of output, but that deterrence and commitment policies also produce a negative effect on stationary employment. The curative approach produces the sharper fall in undeclared work while stimulating stationary output and employment.