A top executive at NSW's Family and Community Services department has been a director of a company which donated to the Liberal party and sought a casino licence, business ventures an expert says conflict with his public service duties.

Fairfax Media revealed last week that top public servant Jim Longley was at the centre of a widening charity payments scandal under investigation by NSW Fair Trading.

Jim Longley, a former Liberal minister and top bureaucrat, was an RSL LifeCare director.

Mr Longley is chief executive of the $3 billion Ageing, Disability and Home Care division and also deputy secretary of the department of Family and Community Services.

FACS runs programs providing support and housing for, among others, people affected by problem gambling.