A man and three teenage boys accused of gang-raping a woman at a pizza shop at Lugarno in Sydney's south-west have been refused bail.

Officers allege the 18-year-old woman met up with a 17-year-old boy she knew — one of the accused — and went to the shop at Lugarno in October.

The pair met another two boys, aged 15 and 17, and a 38-year-old man at the shop.

All four are accused of drugging the woman before repeatedly raping her at the restaurant.

The man is also accused of holding the alleged victim captive for a period of time after the attack, court documents show.

The 38-year-old had the matter mentioned briefly in Liverpool Local Court this morning and chose not to be brought up from the holding cells.

Court documents said the man allegedly deprived the woman of her liberty "for a period after the commission of the offence".

He did not apply for bail and it was formally refused. He will face court again in March.

The teenage offenders also did not apply for bail at Campbelltown Children's Court. It was formally refused.

They will next appear in court on Monday.

Police allege the woman was given an unknown substance before being sexually assaulted several times.

Officers said she was later found by a passer-by at Riverwood.

The woman was treated by paramedics before being taken to Liverpool Hospital.

All four were charged with aggravated sexual assault.