Cemetery for Trees, written and directed by Jessica Nader, won the prizes for best production and best script, and Lily Dougherty collected the best female performer trophy for her role in woMAN. The winners were chosen by professional theatre workers.

Thirty-four productions by students from New South Wales public and private secondary schools and youth theatre groups were entered in this year's event. The competition is for people aged under 18 and the plays must be no longer than 10 minutes in length.

HSPA acting students have won prizes each year since the competition began in 2015, including the best production and best script awards in four out of those five years. The competition is aimed at helping to develop the talents of students who could become professional actors, writers and directors after graduating from school. And that has certainly been the case with some of the HSPA winners.

Cemetery for Trees looks at the impact a meeting with a boy of her own age has on a troubled girl. He has a more positive outlook on life and she finds his humorous comments comforting.

Jessica Nader played the girl, as well as writing and directing the show.

The play's win will see it performed at Sydney's Australian Theatre for Young People (ATYP) and Jessica invited to see shows at that venue and other theatres.

She will also get play texts published by Currency Press.

In woMAN, by Larissa Barwell, Lilly Dougherty was a wife and mother who was very much the head of her family, going to work to earn wages and leaving her husband to be housekeeper and child minder. The win has given Lilly a two-hour acting masterclass with Sydney Theatre Company, a double pass to a show at Belvoir St Theatre, and a workshop of her choice at ATYP.

HSPA acting teacher Andrew O'Callaghan said he was "incredibly proud of the students".

"It was one of the strongest finals ever, with all nine plays covering a diversity of topics and styles," Mr O'Callaghan said.