He was pulled over while driving on July 10. A police officer thought Locke showed signs of being impaired and asked him to do a breath test, but he refused.
Locke was taken to the police station, but refused to provide a blood sample for his blood-alcohol level to be tested.
When Locke appeared in the Christchurch District Court on Tuesday, he indicated he would be representing himself in defending the charge. He told Judge Michael Crosbie he originally wanted the charge to be heard alongside his murder charge, but this was refused.
STUFF
Listen: The 111 call Tristan Locke made after he fatally stabbed his neighbour Mark Cowling during a dispute over noise.