Oxfam has scrapped its paid internship programme and replaced it with a voluntary scheme.
The charity said the paid scheme, in operation since 2002, was ineffective because many interns left Oxfam to work elsewhere or moved to different roles within the organisation.
"Our responsibility to the people who fund us is to spend that money in the best and most effective way," said Oxfam volunteering manager Carolyn Myers. "People who came to us through the paid internship were not choosing to stay in the roles they took on as interns."
A pilot for the new scheme was conducted between September and December 2004.
"We found we were still able to attract the right calibre of people through the voluntary scheme," said Myers. She stressed it was not a cost-cutting measure: "Volunteers help us extend our capacity rather than save us money directly."
The new schemes run for three months or more and offer flexible hours so participants can get part-time jobs. Interns will be given specific responsibilities, from placing aid workers on international projects to conducting their own research.
Sixty roles are available each year for publicity and campaign officers, market research executives, fundraising assistants and deputy retail managers in the charity's network of 750 shops.
"It revamps a very effective career development programme and encourages people who cannot commit to an entire year to join us," said Oxfam spokeswoman Nicola Johnson.