TOKYO—Disappointing growth numbers from Japan show that a weaker yen has failed so far to rev up the nation's export engine, putting a greater onus this year on the nation's consumers.

Japan's growth rate of an annualized 1% in the October-to-December quarter marks the latest cautionary sign among the world's major economies. A further chill could come for Japan in April, when the nation's sales tax rises to 8% from 5%.

Not all the signs are negative. Japanese companies are reporting a pickup in demand for more expensive goods, and the new economic figures released Monday showed a surge in imports, suggesting a rise in confidence that may translate to higher growth later.

For the moment, though, doubts persist about whether Prime Minister Shinzo Abe's push to turn around two decades of lackluster growth has taken root. Overall household spending grew a modest 0.5% in the quarter compared with the previous quarter.

"What's worrisome is consumption," said Masamichi Adachi, senior economist at JPMorgan Securities.