What is the role of a referee in netball?

Answer 1

Netball doesn't have referees they have umpires. Their role is to rule on the plays in a game. If an umpire controls the game very strictly it can slow the game down which can have an impact on the players and enjoyment to spectators. A good umpire will arbitrate on rules allowing some leniency, enabling a fast and smooth game...which makes for an exciting spectacle.

Answer 2

Netball has umpires, not referees.

(See for example Australia's Umpire Accreditation: http://www.netball.asn.au/extra.asp?id=3037&OrgID=1)