It follows the withdrawal of the £20-a-week increase that had been brought in to help people during the pandemic.
The Right Reverend Paul Butler (see photo) says the impact will be severe, plunging more people into debt and poverty.
A government spokesperson said the increase was always going to be a "temporary measure".
Bishop Butler said: "The uplift has been so significant for many families... and families are facing bigger gas, food and electricity bills.
"Simply, families tell us they've only been able to make ends meet due to the extra £20, it needs to stay in place otherwise they risk going back into poverty."
There were particular worries about the impact on children's health and wellbeing, he added.
Along with 13 other senior North East church and faith leaders, he has signed an open letter to the Chancellor of the Exchequer appealing for the uplift to continue. <span style="font-size: 1rem;">Downing Street said the universal credit top-up, which has cost £6bn, was always a "temporary measure".</span>
A government spokesperson said the focus was now on "helping people back into high-quality, well-paid jobs", and "universal credit will continue to provide vital support".