Iain Duncan Smith accused the Government of getting the Treasury to look at the "very worst possibilities" economically if the UK left the EU.
The former Tory leader's warning comes after the Treasury predicted the country would suffer an "immediate and profound" economic shock if it voted in favour of Brexit on June 23.
Duncan Smith told ITV's Good Morning Britain said there were a "number of economists" who didn't agree with the report.
He added that Government supported remaining in the EU and that it had got the Treasury "to look at the very worst possibilities that could happen".
Duncan Smith said that none of the pro-Remain Government reports mentioned the "chaos and crisis that the euro area is bringing".
ITV News asked former Cabinet Office chief economist Jonathan Portes whether or not the UK was headed for a recession.
Chancellor George Osborne has said a Brexit will cause "real damage" and "push our economy into a recession".
Quitting the European Union would plunge Britain into a year-long recession, according to George Osborne.