Four Pakistani immigrant brothers, who repeatedly raped two teenage girls in Sydney last year, were on Thursday convicted and face life imprisonment under new gang rape laws in Australia.

A New South Wales Supreme Court jury found the two eldest brothers, identified as 25-year-old MSK and 23-year-old MAK, guilty of nine counts each of aggravated sexual assault in company. They had pleaded not guilty.

Following the verdict, the court lifted a suppression order on a trial earlier this year where the defendants' two other brothers, aged under 18 at the time of the crime, and another man, aged 25, were convicted of the same crime.

The court was told that the brothers, who raped the girls at knifepoint at their family home in suburban Ashfield in July 2002, 'threatened to kill the girls if they refused to have sex with them'. The girlfriend of one of the brothers told the court that one of the accused told her that they raped the girls 'just for fun'.

The first trial heard that the four brothers had all migrated from Pakistan over the past three years.

In their defence, the brothers had claimed to be victims of an anti-Muslim conspiracy and accused police of fabricating DNA evidence, mobile phone records and other incriminating evidence against them.

Outside the court, detective sergeant Michael O'Rourke said the victims had been subjected to 'abhorrent' sexual attacks. "They've been vindicated today," he said.