Making the firewalls higher and higher will not resolve the crisis, Bundesbank Board member Andreas Dombret said Tuesday. A firewall cannot extinguish a fire. It only buys time until sustainable measures become effective, Dombret said in a speech at the Bank of America Merrill Lynch Global Macro Conference. Monetary policy cannot extinguish the fire either, he added. ECB's policy stance remains rather accommodative. "In effect, monetary policy is more expansive than the key interest rate of 1 percent might suggest," said Dombret. It is definitely not the task of the euro system to substitute for national fiscal policies, central banker said. Greece should stick to the agreed austerity and structural reform measures. "There is no basis for external aid without the agreed reform program," he added.