One of Western Australia's top judges has expressed frustration at the growing workload of the Supreme Court after the State Government decided not to fill a vacancy on the bench.

The court has been operating with only 19 judges since Justice Narelle Johnson retired last year.

Despite pressure from the state's Chief Justice Wayne Martin, and the legal fraternity, which believes it will lead to lengthy delays and a drop in standards, the government has decided another judge isn't needed at this time.

The Attorney General Michael Mischin says the court's own figures indicate it is working efficiently and effectively without the extra judge.

Today, Supreme Court Judge Lindy Jenkins had to postpone a sentencing by a month because of her busy schedule and remarked in open court she would like to know what the Attorney General thinks she does all day.

Mr Mischin has been contacted for further comment.