The University of Sydney's attempts to shut down its art school could lead to a drop in donations from angry philanthropists.

The top end of town has already publicly expressed dismay at the university's plan to close its Sydney College of the Arts at Callan Park in Rozelle.

Sydney's leading gallery owners have signed an open letter calling on the NSW government to preserve the independence of Sydney College of the Arts. Credit:Edwina Pickles

Millionaire arts donor Simon Mordant, former Liberal minister and lobbyist Peter Collins and lord mayor Clover Moore were among scores of people demanding a halt to the closure of the art school in an open letter to Sydney University's chancellor Belinda Hutchinson and vice-chancellor Michael Spence.

Samantha Meers​ and Penelope Seidler​, who between them donated $1.75 million to the university in May, also signed the letter, published in the Herald on Tuesday, which demands an independent review into the art school.