The call is for a Budget that benefits the majority rather than an unaccountable few.
"The Government should reverse damaging austerity, and replace it with a new set of policies providing us with a fair, sustainable and secure future," a spokesperson told Ekklesia.
The People's Assembly is looking and working for alternatives: a living wage, green energy jobs, public stake holding and investment, the Robin Hood Tax on financial transactions, an empty property tax, a bankers bonus' tax, the scrapping of Trident, the creation of affordable housing, rent controls, real action to stop tax avoidance, renewable energy investment, regulation of financial institutions and more.
Simon Barrow, co-director of the Christian political think-tank Ekklesia, commented: "Budgets, we believe, are moral documents. They are not just about abstract figures. They indicate the priorities and vision of a society and the choices facing its elected leaders.
"Economic, monetary and fiscal policies need to be pro-social and pro-environment, because they are about how we share and use our resources. Democratic accountability is also vital.
"We additionally want to raise practical questions about how churches, NGOs and civil society groups use their own economic leverage and investment to promote wider change. Putting money into social housing, credit unions and alternative financial institutions is one important way forward.
"We welcome moves by the Church of England, the Church of Scotland and others in this direction. The churches need to promote a just economy as a core part of their message and mission.
"It is also vital to appreciate that austerity is not a credible economic policy, it is a flawed ideology. We need to invest in change, not cut support for the most vulnerable while bailing out the wealthiest."
The People's Assembly, of which Ekklesia is a supporter, has launched a petition for a #PeoplesBudget. The first set of signatories is being handed into Downing Street in London today.