Barnardo's will launch a campaign to recruit 750 new volunteers after a review of its shops revealed almost all of them were short-staffed.
The charity will attempt to take on more volunteers across its UK-wide network of 365 shops in a PR campaign that will start on 12 September and last until the end of the year.
John Ellis, deputy director of volunteering at the charity, told Third Sector: "Barnardo's hasn't recruited enough volunteers in the past. We reviewed our network of shops to find out what they needed, and almost all of them said they needed more volunteers.
"We're optimistic that we'll be able to attract new people. A lot of people are unemployed at the moment, and many high-street shops will be recruiting fewer Christmas staff than usual.
"I hope that as a result of the Mary, Queen of Charity Shops TV series we'll be able to attract a younger demographic who will think it's a trendy thing to do, but we're looking for volunteers of all ages."
A spokeswoman for the charity said Barnardo's had about 5,000 retail volunteers at present, and its new intake would be equivalent to a workforce worth almost £1.4m.