Asia stocks finished mixed on Tuesday as investors took to the sidelines ahead of major central bank monetary policy decisions due later in the week.

Australia's ASX 200 fell 15.76 points, or 0.3 percent, to 5,220.60, led by declines in the energy and materials sub-indexes. Japan's was off 86.02 points, or 0.49 percent, to 17,353.28, while the Kospi wavered between positive and negative territory before closing up 5.08 points, or 0.25 percent, at 2,019.63.