The man accused of murdering New Zealander Andy Marshall was on a cocktail of drugs and alcohol when he pushed him through a bar window to his death.

Marshall, 29, from Feilding, fell five metres after being pushed through the window of a two-storey Perth bar on to a concrete footpath. He died in hospital hours later.

Stefan Pahia Schmidt, 26, is on trial at the Supreme Court of Western Australia for Marshall's murder. He has admitted pushing Marshall but his defence maintains the death was a "horrible accident".

Marshall is slain Feilding farmer Scott Guy's cousin. Guy's brother-in-law, Ewen Macdonald, is on trial in Wellington accused of his murder.

Marshall was killed on May 8 last year, a little under a year after Guy was found shot twice in the face and throat at the end of his driveway.

As the trial continues in Australia, the jury heard how Schmidt took issue with a supposed "look" Marshall gave him just moments before he was pushed out the window.

Both were drinking early in the night at the Cottesloe's Ocean Beach Hotel, when Schmidt asked two of his female friends - who Marshall was speaking to at the time - to leave the hotel.

"He turned around and gave me a look ... a look of 'what's going on?', 'who are you?'" Schmidt said.

"He said something back to me [after I told him to 'f*** off'], and that's when I pushed him.

"He was trying to interfere."

Schmidt described the push that propelled Marshall through the window as a "general 'go away'".

"I wasn't interested in him... I wasn't sizing him up.

"I was unaware where I was pushing him to."

He said the push was a "bit more than medium", but was not intended to hurt Marshall.

Schmidt told the court he'd earlier taken two ecstasy tablets, smoked several marijuana joints and had started drinking alcohol about 10.30am.

However, he said the ecstasy did not affect him.

"It keeps me awake, keeps me going, puts me in a good mood, so to speak," he said.

"Overall, I was happy. I wasn't incoherent. The mood was generally happy."

Schmidt said he arrived at the hotel with a group of about 15 friends about 4.30pm.

The jury heard that evening was going well until an altercation between himself and one of his friends regarding a girl, Stella Paki, a "sister" to the pair.

After the fight Schmidt said he felt annoyed and upset, and decided to diffuse the fight by asking Paki to leave.

When he went to speak with the girls, Schmidt saw them talking to Marshall.

Schmidt was reportedly on the verge of tears as he recalled the incident to the jury.

"I was in disbelief. I couldn't even comprehend what had happened," he said.

"All I could think was: 'Just get home'.''

Schmidt did not go down to help Marshall. Instead, witnesses have recalled how he left the scene, apparently "emotionless" over what had just happened.

"I was scared. I wasn't trying to run away from the scene of a crime," he told the jury.

Schmidt said he pushed another man on the way out of the bar because he felt "scared and intimidated".

After leaving the hotel, he saw Marshall on the footpath being treated before catching a taxi home.

He said he was "shocked and confused" and "burst into tears" when he found out Marshall had died.

The next day he organised to hand himself into police.

The judge was expected to begin summing up today.

Fairfax NZ and WA Today