A police constable, who was allegedly driving while disqualified, has pleaded not guilty to criminal charges over a car crash in Tasmania that killed a woman and her teenage son.

Cassandra Joy Richardson, 26, has been stood down from duty since the collision near Penna, in the state's rural southeast, in May 2022.

She was in October charged with two counts of causing death by negligent driving, driving while disqualified, driving without due care and attention and two counts of contravening vehicle standards.

The multi-car crash killed a 50-year-old woman and 16-year-old boy, while others were injured.

Richardson, who Tasmania Police says was off duty at the time of the crash, briefly appeared in Hobart Magistrates Court on Tuesday and pleaded not guilty to all charges.

She is expected to next appear in court on April 21. Her bail was continued.