In the aftermath of the financial crisis, the role of monetary policy and macro-prudential regulation in promoting financial stability is under discussion. The old debate concerning whether monetary policy should respond to credit and asset price bubbles was revived, whereas macro-prudential regulation is being assessed as an alternative macroeconomic tool to deal with financial imbalances. The paper explores both sides of the debate in a New Keynesian framework with financial frictions by comparing the welfare and stabilisation impacts of distinct policy regimes. First, we investigate whether there is a welfare benefit from monetary policy leaning against financial instability. We show that monetary policy rules of this type perform better than conventional monetary rules. Second, by introducing macro-prudential regulation in the model, results from optimal policy analysis suggest also that there are welfare gains, even in the case in which monetary and macro-prudential authorities are independent and react to their own policy goal.