The government on Thursday said it is planning legal changes to make it easier to detain psychiatric patients with violent tendencies.

Mental health has been in the spotlight following a string of violent incidents in the past few months, and officials say the proposed move balances factors such as patients' rights and health, as well as public safety.

Under the plan, mandatory detention orders would be extended to people who are admitted to hospital voluntarily and are found to have a criminal record for violence.

It will also apply to those who act violently or have a tendency to become "criminally violent" in hospital.

When they are allowed out, patients would be subject to conditions, including checks to ensure they are taking their medication.

"For example, using telemedicine to witness patients taking their pills, counting the number of pills left in every follow-up or home visits," the Undersecretary for Health Libby Lee said after attending a meeting of the Advisory Committee on Mental Health.

"[Doctors] could even require blood or urine tests to ensure the drug level in the plasma level reaches a certain extent," she said.

Meanwhile, she said that patients under a conditional discharge order – which require them to stay in certain places, take prescribed medication or attend follow-up sessions after they are discharged – currently need to apply to have the order removed.

She said authorities will add an automatic review mechanism so that these conditions will be reviewed at least once every two years.