A woman who died in a petrol-fuelled blaze in Sydney's west six years ago did not set herself alight, a jury has been told, but "something extreme happened" in her relationship with her husband shortly before her death.

Parwinder Kaur, 32, died in hospital from severe burns in December 2013, the day after a neighbour heard a piercing scream and saw her running down the driveway of her Rouse Hill home while on fire from the neck down.

Kulwinder Singh leaves court this week. Credit:AAP

Her husband Kulwinder Singh, 41, is on trial in the NSW Supreme Court accused of her murder. Mr Singh has pleaded not guilty and says he ran downstairs to find his wife already ablaze.

In a closing address on Wednesday, prosecutor Chris Maxwell, QC, said the Crown case is that Mr Singh was not upstairs at the time Ms Kaur's scream "shattered the afternoon quietness" of their home.