Under these government schemes, workers must work without pay or see their benefits withdrawn.
Christianity Uncut, a network of Christians campaigning against the UK government's cuts agenda, is writing to the charities to urge them to withdraw from the schemes as a public witness against forced labour.
The call comes at the start of a week of action against workfare.
The action has been called by the group Boycott Workfare for the week of 18-24 March.
During the week, Christianity Uncut is planning to write to all Christian organisations using workfare labour.
"Workfare workers are not volunteers - their work is not voluntary but obligatory, and they should be paid a living wage,” said Chris Wood, a spokesperson for Christianity Uncut. “Instead they are being threatened with losing the benefits on which they live if they refuse to take part in this forced labour scheme.”
Wood added, "We are deeply saddened that charities such as the Salvation Army and YMCA are undermining the good work they do, and their witness to Christ, by participating in workfare schemes. Throughout the economy, workfare is increasing poverty and unemployment by reducing the jobs available for paid staff. Christians need to make a public witness against workfare.”
He quoted Jesus' teaching that “The worker is worthy of his pay” (Luke 10,7).
Christianity Uncut welcomed the fact that most churches and Christian organisations are not participating in workfare. They encouraged them to sign the pledge promising that they will not do so in future.
The Salvation Army and the YMCA have both defended their use of workfare labour in recent statements.
The YMCA said they “find it difficult to condemn any scheme which carries potential to help individuals gain new skills or prepare for future employment.”
Protests, creative actions and online pickets against workfare will take place on 18-24 March across the UK in a week of action called by the Boycott Workfare network to escalate the campaign against forced unpaid work.
Christianity Uncut is an informal network of Christians campaigning against the UK government's cuts agenda and the wider injustices of capitalism.
They are committed to active nonviolence, rejecting both violence and passivity.