The Countryside Agency has called for more funding to sustain a pioneering walking scheme in the West Midlands.
Angela Smith, the CA's Walking for Health coordinator, said there were concerns about the long-term future of the region's Walking the Way to Health initiative.
Lottery funding for project, designed to increase people's activity levels and improve their health, is to be withdrawn in October.
While the projects run by the scheme are expected to continue for a further 12-18 months, there are fears that without further backing many may be unable to carry on beyond that. The funding call comes on the back of an investment boost for the scheme.
Ms Smith said she welcomed an additional £75,000 awarded to six groups in the region as part of the Forestry Commission's Active Woods campaign, but warned that more central funding would be required to guarantee the long- term future of the scheme.
"Although this grant from the Forestry Commission is most welcome, what the schemes need now is to have their projects mainstreamed into partner organisations, such as Primary Care Trusts, district and county councils, and the voluntary sector as well as the Forestry Commission, Government Office or Sport England to ensure their continued success", she said.
"Statistics show that seven out of ten people don't do enough exercise. The initiative has proved to be an effective and simple way to increase people's physical activity levels and improve their health."
The Walking for Health Initiative is run by the Countryside Agency with support from The British Heart Foundation and, until October, the Big Lottery Fund.
Its goal is to get people walking regularly to improve health.
WHI began in October 2000 and aims to get over a million people walking regularly by the end of this year.