New Zealand scientists are developing a long-acting ketamine tablet, which could change therapeutic delivery of the drug.

They're aiming to create a tablet patients can take at home once or twice a week, for treatment-resistant depression.

The pill is now being pushed towards regulatory approval in the United States, to make it widely available.

Otago University professor, Paul Glue, says it's a big change from current ketamine therapy.

"If you're getting the injection, it's got to be done in a clinic. You're going to be off your face, you're going to be very sedated, very spaced out - your blood pressure can go up." 

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