The main Christian denominations are being urged to scale up their efforts to alleviate poverty in the UK.
The open letter has been signed by over 350 ministers across the UK and asks leaders of the main Churches to ensure that "the deepening crisis of UK poverty is at the centre of national attention".
The church leaders say they are "compelled to speak truth to power" and stand with "those whose voices are consistently ignored by those in power in corporate, media and public life".
It urges Churches to "redouble our efforts not just to alleviate the symptoms of poverty, but to call out the root causes, systems and structures which ensnare so many in poverty today".
"Poverty and gross inequality are not acts of God but structural defects that can be corrected," the letter reads.
"Speaking truth to power is a task for the whole Church, and one given greater urgency now, amid political debates that continue to expose the divisions within society."
The letter has been released ahead of Church Action on Poverty Sunday on February 23 and envisions a "church at the margins", providing a place of welcome to those on the margins of society.
"At national level, we call on our church institutions to commit to the task of becoming a true church at the margins and to properly resource this, as a genuine expression of the gospel priority for the poorest and most vulnerable," it reads.
Niall Cooper, director of Church Action on Poverty, praised local churches for their efforts to address poverty in their local communities but said it was time for the whole Church to act.
"The church must hear the cry of the poor and act. It must step alongside those who have been swept into poverty and work with them to challenge the systems that pull people down," he said.
"Many churches are doing wonderful work in their own neighbourhoods, but we need such action everywhere, and national leaders must prioritise that.
"We thank everyone who has signed this letter, and hope it begins a sea-change in the priorities of the church as a whole."
Rev Andy Delmege, director of the National Estate Churches Network, is one of the people to have signed the letter. He said it was "more vital than ever that our churches prioritise communities that are being ignored, pushed aside and left behind".
"We must ensure that every community can flourish, bringing God's love and hope to those in need," he said.
Rev Adam Maynard, vicar of St George's Everton, said he had signed the letter because society and the Church were not doing enough to address the causes, impact and reality of poverty in the UK.
"As those who worship and seek to follow the one who emptied himself for sake of the world, we owe it to our Saviour to move beyond two-dimensional ideas about poverty and to seek to challenge and engage with the reality of it in thought, word and action," he said.
Martin Green, a trustee of Church Action on Poverty who himself has experienced food poverty, said that many churches are good at helping people on the street at the local level, but could do more at a national level to challenge the causes of poverty.
"With more church support, other people would also listen more to people in poverty," he said.
The letter can be signed at www.church-poverty.org.uk/what-we-do/poorchurch/