The worst affected cases are low-priority drugs matters while analysis of computers for offences such as possessing child pornography can take up to five months.

Magistrates have the power to make fast-track orders for cases that require quicker drug and DNA analysis, but Newcastle Local Court heard last week that items in the fast-track queue might not be tested until the end of this month.

One prosecutor told the court that fast-track samples could take "some months" to be tested.

A spokesman for Police Minister Michael Daley said police had the flexibility to prioritise what samples the Department of Analytical Laboratories tested.

"Currently, cases where an offender is in custody or a court date has been set are processed as a priority and it is important that police have this flexibility," the spokesman said.

Drug samples are not only tested to determine what a substance is, but the laboratory is responsible for removing drugs from the containers or bags in which they are found and then weighing the drugs.

The exact weight of the drug, minus the packaging, can be the difference between a possession charge and the more serious supply charges.

One defendant who faced Newcastle Local Court recently on minor drugs charges was told by a magistrate: "It may be this year, it might be next year that the drugs are weighed properly."

In another case, a prosecutor recently sought a four-month adjournment in a child sexual abuse case because five computers had been seized and needed to be analysed.

The prosecutor said there was a four- to five-month backlog for computer analysis.

The police officer in charge of the investigation was waiting on a call from the laboratory so he could view material on the computers with the help of a technician, the prosecutor said.

"It could take a couple of weeks, it could be several months," the prosecutor said.