HONG KONG, May 4 (Reuters) - Private business activity in Hong Kong continued to shrink in April for a 10th successive month on sluggish global demand, although the decline was the slowest since September, a purchasing managers' survey showed on Monday.

The Hong Kong purchasing managers' index (PMI) in April remained well below 50, which means business activity continued to contract, although the index edged up to a seasonally adjusted 44.3 from 42.7 in March.