Retail sales rose decidedly less sharply in January than in the final three months of 1978, the government reported yesterday -- suggesting that consumers may be beginning to curtail their spending after last quarter's apparent spree.

Commerce Department figures showed overall retail sales levels up 0.4 percent last month, compared to a revised 1.3 percent jump in December. Previously, the department had reported the December increase as only 1 percent.

The January rise came entirely in sales of non-durable goods. Sales of durable goods declined by 0.9 percent over the month despite an 0.5 percent rise in retail auto sales. Sales levels in January were at a seasonally adjusted $69.7 billion, up from $69.44 billion in December.

The tapering off in January was expected by most economists. Analysts had cautioned the economy would not continue at the robust pace it reached last quarter -- a relief for the Carter administration, which had been fearful the gains would exacerbate inflation.

Courtenay M. Slater, the Commerce Department's chief economist, said the 0.4 percent rise was particularly robust when viewed in the context of the especially sharp increases of the three previous months. She said the economy now was on track in line with predictions.

January's report placed overall retail sales levels 16.2 percent above those of a year ago, with sales of durable goods up 19.8 percent and sales of non-durables up 14.4 percent. There were year-over-year gains in every major category. Apparel and accessory sales rose 23 percent.