The slump in Poland's manufacturing sector deepened in May, a survey showed, as declines in output, new orders and employment accelerated.

S&P Global's Polish manufacturing Purchasing Managers' Index (PMI) fell to 45.0 in May from 45.9 in April, remaining below the 50.0 line that separates growth from contraction for the 25th month in a row. Analysts polled by Reuters had expected a reading of 47.1.

"Poland's manufacturing downturn showed no sign of ending in May," Trevor Balchin, economics director at S&P Global Market Intelligence, said in a statement.

"The weaker Polish data are at odds with the latest flash euro zone figures, as manufacturing production in the single currency bloc moved towards stability."

The current sequence of contractions is the longest since the survey began in 1998.

Demand continued to weaken, with new orders falling for the 27th month running. Companies said that poor market conditions domestically and internationally weighed on new orders.

Meanwhile, employment declined as companies said they were not replacing staff who left, due to high labour costs.

However, sentiment regarding the year ahead was positive, with respondents pointing to expectations of an economic recovery. (Reporting by Alan Charlish; Editing by Susan Fenton)