Circumcision rates for newborn boys in NSW have jumped by more than 30 per cent in the past two decades, and there is now a call for the procedure to be reintroduced in public hospitals.

Sydney University professor of medicine Brian Morris claims the latest evidence shows the operation is "equivalent to childhood vaccination" and it is "unethical" not to offer the procedure to all parents as a matter of routine.

He has written to NSW Health Minister Jillian Skinner urging her to lift the ban on elective circumcisions in public hospitals, claiming the cost savings in diseases and adverse medical conditions will be "massive".

About one in six - or 8100 - infant boys in NSW were circumcised in 2012, more than twice the number of any other state. It is an increase from one in eight in 1994, despite the procedure being banned in public hospitals since 2006, unless medically necessary.

Paediatrician Howard Chilton says a greater acceptance of "health advantages", such as reduced risk of urinary tract infections, means more parents are choosing to circumcise boys, usually before they are six weeks old.