Within Asia, the Japanese and Singaporean economies could struggle the most in the coronavirus pandemic, an economist from Moody's Analytics said on Monday.

Both economies were already weak before the outbreak worsened over the past month — and stricter lockdown measures imposed to contain the virus spread will likely exacerbate their respective economic troubles, said Steve Cochrane, the firm's chief Asia Pacific economist.

Latest official data in Japan showed the economy shrinking by 6.3% year over year in the three months to December, while preliminary estimates in Singapore indicated that the economy contracted by 2.2% in the quarter that ended in March.

"Japan already was in recession coming into this; the first quarter for Singapore was very weak, I think this quarter will be even tougher for Singapore given the lockdown," Cochrane told CNBC's "Squawk Box Asia."

"And then there is potential that in Japan, if the coronavirus spreads further, there could be more of a real lockdown rather than the kind of a soft lockdown that's in Japan right now," he added.