A teenager has been charged today with allegedly assaulting two elderly women during a string of home invasions in south-western Sydney last week.

The 18-year-old boy was arrested yesterday when police raided a home at Merrylands and seized items linked to their investigation.

He’s accused of breaking into five homes in Merrylands between 4am and 6am last Thursday.

In two of the separate home invasions, women in their 80s were allegedly sexually assaulted and touched.

At one of the homes, the man is accused of holding a knife while attempting to sexually assault a woman. In another home, he allegedly sexually touched a second woman.

Crime scenes were established at each home, and an investigation into the attacks by detectives from Strike Force Beigy began.

The man was arrested at Dee Why police station on the Northern Beaches and faces 16 charges, including armed, aggravated sex assault, break and enter, and sexually touching without consent.

He was refused bail and is scheduled to appear in court later today.