OTTAWA -- The arms-length agency that processes refugee claims in Canada estimated it would need twice as much money as it will ultimately receive to significantly tackle a major backlog in asylum claims, caused in part from an influx of irregular migrants.

Documents obtained under access-to-information law show the Immigration and Refugee Board drafted costing estimates in November 2017 showing it would need $140 million annually plus an additional $40 million in one-time costs to finalize 36,000 extra refugee cases every year.

That's how many cases the board would need to complete to cut the backlog and also meet the current intake of new asylum claims.

The government ultimately earmarked $74 million to the IRB over two years in last year's federal budget to address Canada's refugee backlog, which currently stands at over 64,000.

The IRB says in the documents the amount will not be enough to finalize the outstanding claims within two years and that a longer-term strategy is needed to tackle the problem.

The documents also reveal employees processing the claims have raised concerns about heavy workloads, problems with their pay due to the Phoenix pay system and have pressed management about when the influx of claims will be considered a crisis.