The SABB HSBC Saudi Arabia Purchasing Managers' Index, which measures activity in the manufacturing and services sectors, was 60.39 points in May against 60.42 in April. The seasonally adjusted index stayed well above the 50-point mark separating growth from contraction.

Growth in new orders was the highest in 11 months, at 70.57 points in May against 70.13 in April. "Where new order inflows increased since April, this was commonly linked by panel members to a general improvement in market conditions," the survey said, noting that foreign demand for Saudi Arabia's non-oil exports continued to expand in line with historical growth rates.

Output growth declined slightly to 63.05 in May from 65.20 in April. Employment growth also eased moderately.

However, input price inflation remained well above its historical trend because of the rising cost of materials, although it was down slightly from April's record high.

Analysts in a Reuters poll conducted in March predicted Saudi Arabia's gross domestic product would expand 4.5 percent this year, after an officially estimated 6.8 percent last year.