In a letter described as a "blunder", Iain Duncan Smith, UK Work and Pensions Secretary, has said it will need a two-year study to look at the effects of the controversial policy.
Despite several reports, studies and anecdotal evidence all pointing to a huge increase in arrears since the under-occupancy penalty was introduced last April, Mr Duncan Smith denies it is to blame.
Last July, just three months after its introduction, the Evening Times surveyed housing associations in Glasgow and found overwhelmingly they were witnessing an increase in rent arrears.
Small, medium and large associations all said there was an increase on the previous year and many of the tenants affected by the policy were getting into arrears or falling further behind than before.
A Scottish Government report in October showed an arrears increase of £800,000, coinciding with the introduction of the 'bedroom tax'.
Mr Duncan Smith wrote to Michael McMahon, convener of the Scottish Parliament Welfare Reform Committee, in response to a number of concerns the committee raised.
He wrote; "On the issue of arrears, it is simply too early to say that they are increasing because of the removal of the spare room subsidy.
"We need to carefully monitor the evidence over time and that is why we have commissioned an independent, two- year evaluation on the effects of the removal of the spare room subsidy."
Last year the Evening Times found in the first three months, social landlords facing substantial loss of income through arrears.
Queens Cross HA, in the north of the city, said almost all of the 330 tenants affected were in arrears.
Blochairn HA, in the north east, said 65% of those affected were now in arrears, and New Gorbals, in the south, said of a possible £52,000 of arrears it was carrying £15,000.
Whiteinch and Scotstoun HA, in the west, said it had £8000 of 'bedroom tax' arrears, more than half the extra tenants were expected to pay.
Linda Fabiani, SNP MSP member of the Welfare Reform Committee, said Mr Duncan Smith was in denial.
She said: "Iain Duncan Smith has blundered yet again on a topic he should be up to speed on, he was the man who implemented the iniquitous 'bedroom tax' in the first place.
"The letter shows that he is in denial on the devastating consequences of the tax on vulnerable people across Scotland.
"This comes after the announcement by George Osborne that, on the Treasury's current forecasts, £12 billion of further welfare cuts will be made by Westminster in the first two years of the next UK Parliament.
"He suggested housing benefits for under-25s would be cut, affecting 32,000 households across Scotland - and plunging another 20,000 children in Scotland into poverty."