A move by the Bank of Japan to raise interest rates this month would likely come too soon after the formation of Sanae Takaichi’s administration and would be better timed in December, according to one of her closest economic advisers.

"A rate hike in October is probably difficult in my view,” said Etsuro Honda, who advises Takaichi on economic policies, in an interview on Monday. "It depends on the macroeconomic environment, but I don’t see a problem if it’s raised by 25 basis points in December.”

Honda’s remarks suggest the likelihood of the BOJ waiting before raising its policy rate, despite earlier speculation of an October move, following Takaichi’s victory in the ruling party’s leadership race on Saturday.

Takaichi, a known advocate of monetary easing and protege of former Prime Minister Shinzo Abe, is expected to become Japan’s first female prime minister in a parliamentary vote around Oct. 15.

Honda is known as one of the principal architects of Abenomics, the flexible fiscal and easy monetary policy stance of Takaichi’s mentor.

Under Abenomics, the BOJ and the government reached an agreement on overall policy goals, while leaving the details and approach to the central bank. That agreement is still in force today.

Takaichi wants the BOJ to proceed cautiously with interest rate increases, though she hasn’t mentioned a specific time frame for hikes, Honda said.

Honda has advised Takaichi particularly closely in the last two years. He wrote a section on economics for Takaichi’s "Study of National Power” book last year.

Takaichi surprised some investors with her Liberal Democratic Party leadership victory, given that her rival Shinjiro Koizumi appeared to be the front-runner. The Nikkei 225 stock index surged to a record high Monday and the yen weakened against the dollar beyond the key threshold of ¥150, on expectations of more stimulus and slower rate hikes from the central bank.

"Too much weakening of the yen will impact inflation and will keep it elevated,” Honda said. "It’s a little hard to say what the desirable level is but if it goes beyond ¥150 it’s a bit too much.”

Following Takaichi’s victory, bets plunged for a rate hike on Oct. 30 when the bank delivers its next policy decision. Traders saw around a 25% chance of the move Monday, falling from around 68% less than a week ago, according to overnight indexed swaps.

Last year, Takaichi described raising interest rates at the time as "stupid.” While she toned down her messaging in the latest LDP campaign, she said in a survey that rates should remain unchanged for now, according to Kyodo News last week.

While Takaichi’s win may have pulled back expectations for a hike this month, economic data points to Japan largely following the central bank’s projections.

Inflation has stayed at or above the BOJ’s 2% target for more than three years and the country’s economy expanded for a fifth straight quarter in the three months through June.

For the first time since Gov. Kazuo Ueda’s term began, two out of the nine BOJ board members voted against keeping the rate on hold at 0.5% last month, citing strength in inflation. Another board member who is seen as dovish said last week that there is a rising need for a rate hike. Both factors fed into rising expectations of a looming rate move among investors.

One potential shift BOJ watchers are monitoring is a revision of the joint statement made by the central bank and the government in 2013. That agreement formed the rationale for the bank’s aggressive monetary easing in pursuit of 2% inflation for more than a decade, before Ueda began normalizing policy.

After her election win on Saturday, Takaichi said that she’ll think about whether the current form of the accord is the best.

"I’ve told her that there is no rush to change it,” Honda said. "Once it’s considered, things that don’t have to be revised now can be revised, including the 2% price stability target.”

In terms of tackling a key diplomatic task, Honda expects Takaichi will establish a positive partnership with U.S. President Donald Trump because of her close ties with former Abe. That was more of a challenge for outgoing Prime Minister Shigeru Ishiba, who struggled on that front, Honda said.

"President Trump liked Abe, but Ishiba wasn’t close to Abe,” Honda said. "Takaichi is from the same camp as Abe and I think she can forge a cordial relationship with the president.”