NSW trainer Paul Murray has been banned for 3-1/2 years for cobalt offences relating to stored samples taken from 2013 Doncaster Prelude runner-up Alma's Fury.

Analysis of the post-race samples taken from the gelding showed levels of 890 and 940 micrograms per litre of urine.

A cobalt threshold of 200mcg/L was introduced in January 2015 and halved from September last year.

Racing NSW stewards rejected arguments by counsel for Murray that cobalt was not a prohibited substance at the time because there was no threshold in place.

Stewards found a substance labelled "concentrated trace mineral" in a fridge during a stable inspection in June 2014.

Murray was disqualified on Wednesday for a total of seven years on four charges relating to the cobalt results and the "concentrated trace mineral".

Stewards took into account there was commonality among the charges and his sentences should be served concurrently, reducing his ban to 3-1/2 years.

The trainer was also fined $1000 for having unregistered products in the stable.