Banned NRL player Jack de Belin's rape trial may now be delayed until August, dashing the St George Illawarra Dragons forward's prospects of finalising the matter before the 2020 season begins.

De Belin and Shellharbour Sharks player Callan Sinclair were due to begin a two-week trial on February 3 over allegations the pair sexually assaulted a 19-year-old woman in a Wollongong apartment in December 2018.

Jack de Belin (left) leaves Wollongong Court during a break in his case this week. Credit:Kate Geraghty

Both men, who are on conditional bail, have pleaded not guilty to five charges of aggravated sexual assault.

A jury was set to be empanelled on Monday before Wollongong District Court judge Andrew Haesler pushed back the start of the trial to hear a series of complex and sensitive legal arguments, requiring the courtroom to be closed to the public over multiple days.