Adachi, a former economist considered as among those favouring aggressive monetary easing, also said inflationary pressures in Japan were not just being driven up by rising energy costs but also from changing corporate price-setting behaviour.
"As the pandemic shows sign of subsiding, companies are gradually starting to hike goods and services prices," Adachi said in a speech on Wednesday.
"In a post-pandemic environment, companies may find good opportunities to raise prices and wages."
Japan's annual wholesale inflation hit a four-decade high of 8.0% in October on rising commodity costs. But core consumer inflation has hovered around zero as soft consumption keeps firms from raising prices.
While Adachi stressed the need to maintain the BOJ's current ultra-loose policy, he said ramping up stimulus would become an option only in extreme cases where a resurgence in infections paralyse the global economy.
"The BOJ must consider taking additional easing steps only if developments surrounding the pandemic lead to a yen spike and stock price fall, and when such market conditions persist," Adachi told a briefing.
Adachi said he was undecided on whether the BOJ should extend a March 2022 deadline for pandemic-relief funding schemes introduced last year to help cash-strapped firms.
"Big firms' funding conditions have improved dramatically with some paying back loans. On the other hand, the Omicron variant is spreading and there's a lot of uncertainty," Adachi said. "I would like to scrutinise developments a bit more."
The BOJ is set to keep monetary policy steady at its next meeting on Dec. 16-17. The board may also decide on the fate of the pandemic-relief programmes.
Adachi shrugged off concern raised by some analysts that recent yen declines could push up import costs and lead to stagflation, where inflation accelerates even as the economy remains in bad shape.
"Personally, I don't think Japan is facing a 'bad weak yen' that could lead to stagflation," Adachi said.
"The yen's recent fall actually is bringing benefits to the economy" by boosting profits Japanese firms reap overseas, he added.
(Reporting by Leika Kihara; Editing by Chang-Ran Kim & Shri Navaratnam)
By Leika Kihara