Over the next year, the 11-year-old - who had never fixed a bike before - and her dad restored over 320 abandoned bikes to donate to children in need.

On Friday, she was named Young Volunteer of the Year at the 2017 NSW Volunteer of the Year Awards.

Tia says her charity, Tell Tia for Charity, is a family effort.

"My dad is the 'mechanic of the family' and used to do a bit of fixing stuff when he was young, and he helps me a lot with fixing the bikes," Tia explained.

"But I've actually learned a few tricks up my sleeve because I went to a workshop at 99 Bikes and learned how to fix the brakes - one trick I learned is to take off the bells and put them back on again, which is something I like to do for a lot of the bikes.

"Tia's little sister is the test-driver too - we send her off on all the bikes!" Tia's mum, Clarissa Brennen, said.

The bikes are donated to disadvantaged children through organisations like the Benevolent Society, Campbelltown Hospital, the Department of Family and Community and Services, and Bike for Life - a charity that gives the bikes to Cambodian children who otherwise have no way of getting to school.

In between school, swimming practice, and running her own charity, Tia also makes her own lip-balm ("watermelon and pineapple flavour") to raise money for the local PCYC, volunteers at One Meal - It Makes a Difference, delivers flowers to a nearby nursing home, and has hosted a toy drive over Christmas for children at the local hospital.

Tia says she hopes to inspire other kids to help others.

"I want to give back to the community, and my most important goal is to show other kids it doesn't matter your age, you can do whatever you want, you can help," she said.

"Volunteer because it's the best thing you could ever do. It makes your heart smile."

Beverly Kerr was named the overall winner at Friday's award ceremony for her work with St Vincent de Paul Society, while Judith Barry, who has spent the past decade volunteering as a court support worker at Mission Australia, won Adult Volunteer of the Year.

Deloitte Australia client services director Robyn de Szoeke received the award for Corporate Individual Volunteer of the Year for seven years' volunteering with Dress for Success Sydney (DFSS), an organisation that provides professional styling, career training and mentoring for women trying to reenter the workforce.

DFSS helped more than 2500 women this year. Even so, Ms de Szoeke, now chair of the board, says certain stories have stood out to her.

"There was a lady who, at a time when we could offer optometrist appointments, had a voucher to go and get glasses, something she hadn't been able to do for many years. And she said she wore them home and her son walked in from school and burst into tears because he knew she could see him for the first time," Ms de Szoeke said.

"To hear the stories of success is really inspirational; to meet the women who are overcoming adversity and challenges, and being bold and brave, is very uplifting."

DFSS Gaol Team - which offers the same styling services to women in prison facing court hearings or preparing for release - also won Volunteer Team of the Year at the Sydney Inner West awards this year.