"I was trying to pick Reeva up and I couldn't, I couldn't pick her up," said Pistorius who told Judge Thokozile Masipa on Tuesday that he fired four quick shots into the toilet when he thought he faced attack from intruders.

In a broken voice murder-accused Oscar Pistorius told the High Court in Pretoria on Wednesday what he did to help his girlfriend Reeva Steenkamp after he shot her in his toilet on Valentine's Day last year.

"I was trying to pick Reeva up and I couldn't, I couldn't pick her up," said Pistorius who told Judge Thokozile Masipa on Tuesday that he fired four quick shots into the toilet when he thought he faced attack from intruders.

At 3.19am he phoned Johan Stander to ask him for help as he was "struggling to pick her up".

He had already tried to phone for help on Steenkamp's phone in the toilet but did not know her password so had gone back to the room to fetch his own.

At 3.20am he called private ambulance service Netcare 911 and although he did not remember speaking to the operator, he remembered being told to take "Reeva to the hospital" and not wait.

He does not remember a call logged to security at 3.21am. He ran downstairs to open the front door to let everyone in.

He has pleaded not guilty to her murder, saying he mistook her for the intruder.

He went back up to the bathroom and picked Steenkamp up.

When he got the second flight of stairs, Stander and his daughter arrived and he was screaming to them to help him get Steenkamp to the hospital.