Sammy Wilson has threatened to name and shame banks failing to help struggling businesses.
His trenchant attack shows Stormont is locked on an apparent collision course with the banks over lifeline lending for local firms.
The furious Finance Minister said some banks - and bank managers - seem "to be totally cut off from reality".
And he revealed he has heard "horrific stories" which appeared to show "banks seem to be determined to put businesses under."
The warning came as he prepared to speak with the main banks and confirmed he is also seeing his counterpart in the Republci Michael Noonan in the next few weeks.
The showdown between Stormont and the banks has been looming for some time, following severe criticism, not just from Mr Wilson but recently from Enterprise Minister Arlene Foster and deputy First Minister Martin McGuinness.
But the tone and language adopted by the Finance Minister is indicative of a worsening relationship between political leaders and the banks following recent signs of a double dip recession.
The remarks in the Assembly followed a call from DUP chairman Lord Morrow for the banks to be "more constructive".
Mr Wilson said just before going into Stormont he had spoken to two people "who, if their side of the story is correct or even half correct, told me the most horrific stories about the way in which banks seem to be determined to put businesses under.
"This week, I will speak with the banks concerned and, at some stage, I think that I will be at the point at which I will name some of them because I am increasingly worried that some banks, or some bank managers, seem to be totally cut off from reality.
"They do not recognise that although they have a commercial responsibility to their organisation, they have a civic responsibility to ensure that they do not stand in the way of economic progress in Northern Ireland."
A Northern Ireland spokesman for the British Bankers Association hit back, however: "Northern Ireland's banks continue to lend to viable businesses and are approving more than eight in 10 applications for borrowing.
"The banks and the BBA have an ongoing dialogue with the minister's office and discussions on the measures banks are taking to help businesses.
"There will always be cases where businesses feel they should be able to borrow but have had their applications declined."
He added: "There is an independently-monitored appeals process in place to ensure these receive the fairest hearing and, where lending is not appropriate, to direct them to alternative sources of finance."
And a spokesman for Ulster Bank said: "We believe in the quality and potential of small businesses in Northern Ireland and we are working with all our customers to provide the support they need.
"This includes understanding the challenges they face and working to reach mutually acceptable solutions.
"Where small business customers find themselves in difficulty we work closely with them with the aim of restoring financial stability to their business."
There was no immediate individual comment from Northern Bank, Bank of Ireland or First Trust.
Mr Wilson, however, also revealed he plans to meet the Republic's Finance Minister Mr Noonan at next month's North South Ministerial Council meeting to discuss potential job losses in the First Trust bank.
He said at an earlier cross- border meeting in April Mr McGuinness and First Minister Peter Robinson had already stressed concerns over the impact job losses would have in Northern Ireland and Irish ministers had indicated the downsizing of staff as a result of bank restructuring (including in the Allied Irish Bank Group / First Trust Bank) was a concern for them also.
"In my discussions with Mr Noonan and his predecessor regarding the potential impact of bank restructuring we have agreed Northern Ireland should not be disproportionately affected by restructuring," he added.
The rate of loan approvals by banks to Northern Ireland firms