Measures that should be under consideration include an exit from yield curve control, negative interest rates and a tweak to the BOJ's commitment to keep expanding its monetary base until inflation stably exceeds 2%, he said in a speech on Thursday.

"It's necessary to consider taking a nimble and flexible response, including on how to exit, or shift gear from the current extremely accommodative monetary policy," he added.

"While there are some economic uncertainties, I feel that we're finally seeing prospects for achieving our 2% inflation target," Takata said, pointing to growing signs of change in companies' long-held practice of forgoing wage and price hikes.

The dollar fell 0.33% to 150.21 yen , while the benchmark 10-year government bond rose 1.5 basis point to 0.710% after the remarks, which market participants interpreted as signalling a strong chance that an unwinding of ultra-loose policy was imminent.

Under its massive stimulus programme, the BOJ currently guides short-term interest rates at minus 0.1%, caps the 10-year government bond yield around 0% and continues to buy huge amounts of assets such as government bonds.

"Takata's comments specifically touching on an exit from YCC and negative rates policy moved markets," said Yoshimasa Maruyama, chief market economist at SMBC Nikko Securities.

"It came as a vivid reminder that policy normalisation is drawing near, although he stopped short of elaborating details on the BOJ's exit strategy.

Earlier this month, Deputy Governor Shinichi Uchida said the BOJ will review other components of its stimulus framework upon ending negative rates.

Sources have told Reuters the BOJ was on track to end negative rates in coming months despite Japan's economy slipping into a recession, on growing signs that companies will continue to offer bumper pay amid a tightening job market.

A Reuters poll showed more than 80% of economists expected the BOJ to pull short-term interest rates out of negative territory in April. A few are betting on a chance of action at the next policy meeting in March.

While many analysts expect the days of negative rates to be numbered, recent reassurances by the BOJ that any subsequent rate hikes will be small have pushed down the yen to around 150 to the dollar - levels seen by markets as heightening the chance of yen-buying intervention by Japanese authorities.

Japan's top currency diplomat Masato Kanda issued a fresh warning against excessive yen falls, telling reporters on the sidelines of a G20 gathering in Sao Paulo that Tokyo was ready to take "appropriate" action if currency moves were deemed too volatile.