No need to doubt our reform vow: Japan minister

Japan remains committed to transforming its economy, which has suffered from years of deflation and weak growth, Toshimutsu Motegi, the country's minister of the economy, trade and industry told CNBC.

Prime Minister Shinzo Abe's radical economic policies, dubbed "Abenomics," have raised hopes of a turnaround in the world's third-largest economy, giving the blue-chip Nikkei stock index a strong leg up this year.

But doubts about the government's commitment to pushing ahead with painful, long-term economic reforms have risen since Abe's ruling coalition secured a decisive win in last month's upper house elections. Abe now has control of both houses of the Japanese parliament.

"Abenomics has been recognized internationally just like Reaganomics and Thatcherism," Motegi told CNBC's Kaori Enjoji in an interview, referring to the economic policies of former U.S. President Ronald Reagan and former British Prime Minister Margaret Thatcher.

(Read More: Japan's 'Abenomics' Will Fail: Ex-Olympus CEO)

"I believe Abe is a reformer. In areas such as economic growth, regulatory reform, we will unfailingly pursue reform," he said.

Kiyoshi Ota | Bloomberg| Getty Images

The government's reform credentials suffered a blow earlier this week amid reports that Abe had commissioned a study into the alternatives of raising Japan's consumption tax, which is due to rise next year. Economists say raising the tax is key to helping alleviate thecountry's high debt levels.

(Read More: Japan's sales tax debate could hit the Nikkei)

On the subject of the weak yen, Motegi said the benefits of currency weakness outweighed the negative impact of a higher bill for imports such as oil.

The yen has weakened about 14 percent so far this year against the dollar, pushed down by aggressive monetary stimulus from the Bank of Japan. A weak currency, which makes Japanese exports more competitive overseas, is a key plank of Abe's economic policies.

"The priority of Abenomics is to end deflation. By correcting an excessively strong yen, exports are growing," Motegi said.

(Read More: Here's what could really knock the yen back down)

"In the short term, there is a problem in that it [a weak yen] does raise fuel costs. But in the current situation, the merits that go beyond just export and import figures are larger," he added.

— By's Dhara Ranasinghe; follow her on Twitter @DharaCNBC