The economy minister on Tuesday rejected the idea of inflation targets as the central bank moves toward tightening its supereasy monetary policy, urging it instead to adopt a flexible approach.

To help spark a recovery, the Bank of Japan has kept interest rates at zero and flooded the financial system with excess cash to encourage lending for about five years.

Signs the economy is emerging from a lengthy slump have fanned expectations the bank will soon start to tighten policy, most likely first by reducing the cash it injects into the banking system.

BOJ officials have said a prerequisite for changing policy is convincing evidence that deflation has been conquered.

Deflation is a state of declining prices that deadens an economy by depressing paychecks and company profits.

But economic and fiscal policy minister Kaoru Yosano said he is opposed to inflation targets, which some experts have suggested as a solution, saying such a measure may restrict the bank's policy.

"If you put too rigid of a framework on it, the BOJ will lose flexibility in monetary policy and that would in turn be a minus for the Japanese economy," he told reporters.

"Setting up a target before that doesn't work from the standpoint of economic policy," he said.

Over the weekend and Monday, Yosano and other politicians suggested the central bank won't face much opposition from the government when it decides to tighten monetary policy. In the past, they have repeatedly urged caution.

While the BOJ is officially independent of the government, political opinion often has had an influence on central bank policy.

Finance Minister Sadakazu Tanigaki reiterated that deflation remains, although he softened his tone compared with the past.

"I want the BOJ to look at the economic situation broadly and judge policy in a cool-headed manner," he said.