Both women name suppression.
On the day of the alleged attack, the women were sleeping on a mattress in the lounge of a house in Porirua.
Hemopo entered the lounge and demanded cigarettes. When none were given, he left the room and returned with a hammer, Mr Burston said.
He allegedly attacked the women and hit one of them with a hammer, he said.
That woman suffered a fractured elbow, a fractured shoulder blade, an injured spine and a cut on her arm.
She was able to escape and called police but Hemopo took the other into a bedroom to continue the attack, Mr Burston said.
He said the words to the effect that he had to kill her, before cutting her throat with a knife, Mr Burston said.
Hemopo then cut his own throat, he said.
Police arrived to find Hemopo standing over the woman attacking her, so they both simultaneously discharged their weapons - a Taser and a gun, he said.
Hemopo told the jury the incidents that the women alleged happened were not true.
"I ask you all doing jury for the next few days to listen to all the evidence and most importantly, to keep an open mind."
The two complainants were not telling the truth, he said.
"I ask you not to pre-judge," he said.
The Crown is expected to call 34 witnesses during the trial, which was set down for a week.
The trial continues.