A friend of a man accused of murdering his fiancee says the two seemed to have a normal relationship before her death.

Simon Gittany is accused of throwing Lisa Harnum over the balcony of their 15th floor apartment in the Sydney CBD in July 2011.

His friend of 25 years has given evidence in the Supreme Court.

Peter Mourgelas says Gittany and Miss Harnum were known to have “a few spats”, but were otherwise normal.

Mr Mourgelas has also described an incident where the three of them were on a car trip to Strathfield in Sydney’s inner west.

He says Miss Harnum became upset, took her seatbelt off, opened the car door, and made it look like she was going to get out while it was moving.

He says he felt she was doing it for attention.

Mr Mourgelas also said that during the spats, Lisa Harnum would be angry but Gittany would remain calm.

Gittany has previously given evidence admitting he was a jealous lover who was frustrated after Miss Harnum told him she had a “secret”.

The 40-year-old installed security cameras in their apartment, but rejected claims it was to spy on his fiancee.

He has admitted using computer software to monitor her text messages and found out that she was planning to remove her possessions from the home.

Lisa Harnum had confessed that she was unhappy at times, and talked about moving to Melbourne or back to her homeland in Canada.

Simon Gittany maintains she threw herself off the balcony.

The trial continues before Justice Lucy McCallum.