The underwriter's gross written premiums rose 7 percent to $583 million (402 million pounds) in the quarter ended March 31 with its largest division, specialty lines, reporting a 15 percent increase to $261 million.

The insurer's U.S. specialty lines business caters for the professional liability and management liability needs of small and mid-sized organisations.

Beazley, which provides marine, casualty and property insurance and reinsurance, also said claims notifications in the first quarter were "encouraging" and it expected its first-half combined ratio to be better than average if the trend continues.

Shares in the company were up 1.8 percent at 335.5 pence at 0803 GMT on Thursday on the London Stock Exchange.

Gross written premiums for marine insurance fell 7 percent during the period, while life, accident and health jumped 33 percent to $48 million.

Premium rates on renewal fell one percent during the period, the insurer said, adding that the rating environment remained highly competitive, mainly for large risk and catastrophe exposed lines of business.

J.P Morgan Cazenove analyst Edward Morris said this was a strong result for Beazley against the current backdrop, with a 2 percent premium renewal rate increase for specialty lines helping to offset continued declines in other areas.

Over the past few years, insurance rates have either stagnated or fallen due to fierce competition.

(Reporting by Noor Zainab Hussain; editing by David Clarke)