April 25 (Reuters) - Principal Financial Group reported a rise in its first-quarter profit on Thursday, helped by higher premiums and income from investments.

Wage growth and a tight labor market have ensured job security, while heightened expectations of a soft landing have boosted confidence among businesses, allowing them to revive spending on insurance policies.

Premium and fees from PFG's specialty benefits business, which provides employee benefit plans to small- and mid-sized businesses, rose 8% to $801.3 million in the quarter ended March 31.

A higher-for-longer interest rate environment maintained by the U.S. Federal Reserve has also helped insurers rake in more from fixed-income investments.

PFG's first-quarter net investment income came in at $1.07 billion, compared with $986.7 million a year earlier.

Adjusted operating earnings were $394.3 million, or $1.65 per share, in the January-March quarter versus $366.8 million, or $1.48 per share, a year ago.

The Des Moines, Iowa-based company's assets under management rose 7% to $708.5 billion. (Reporting by Pritam Biswas in Bengaluru; Editing by Shilpi Majumdar)