The unit's members have experience dealing with Canada Pension Plan disability cases, says a spokesman for the employment and social development department.
They're currently plowing through outstanding cases in an effort to eliminate the backlog by the end of this summer.
But a source close to the tribunal said it was never consulted about the spike unit, nor did it get a heads-up prior to former employment minister Jason Kenney disclosing details of the plan last month.
The source — who spoke on condition of anonymity because the individual wasn't authorized to discuss the matter publicly — says the tribunal hasn't been told who's on the unit, what their qualifications are, and if they operate at arm's length from the government.
Michael Prince, a public policy professor at the University of Victoria who's been critical of the government's efforts to streamline the social security appeals process, says the spike unit raises concerns.
"It's a patchwork, ad-hoc response that underscores their bad management of this whole file right from the get-go," Prince said in an interview.
"They're taking heat politically, so they respond politically by creating a quick-response team ... but there's a jurisprudence and a body of law around this tribunal that needs to be respected."
Rather than having departmental experts wrestle the backlog, Prince added, the government should have beefed up the tribunal, which wasn't fully staffed until last fall, more than 18 months after it began operation.
Prince said the Conservatives also should have provided proper funding and resources to the former office for the commissioner for review tribunals in its final year of operation to ensure the new tribunal wasn't inheriting an unmanageably large backlog of cases from the system it replaced.
Simon Rivet, a spokesman for the Employment and Social Development Canada, said in an email it's too early to provide details about the spike unit's decisions so far.
He said departmental "experts" are taking a second look at cases and will offer settlements to those who have now been determined to meet the CPP disability eligibility criteria after providing new information.
"While we are working expeditiously to address the inventory, all cases are being treated factually and fairly using the existing eligibility criteria of the program," Rivet said.
"Cases that are not settled by the department through this approach will continue to a hearing at the SST."
The federal government launched the social security tribunal in April 2013 to streamline the appeals process and save Canadian taxpayers $25 million a year.
But since then, the backlog of cases has ballooned to more than 11,000, most of them involving sick or injured Canadians denied CPP disability benefits.
Last week, the Finance Department's monthly fiscal monitor showed the government grew its surplus for December, compared with a year ago, as revenues increased and spending fell.
Ottawa posted a surplus of nearly $2.43 billion in December compared with a surplus of $1.20 billion in December 2013.
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