Labour, Home Affairs and Housing Minister David Burch has said nightshifts could be used to clear the work permit backlog.

Employers groups have been complaining about waiting up to five months to get a work permit approved and Sen. Burch said the fast track work permit process, primarily used by international business, had been part of the problem.

He said: "All we have done is created an added burden for the people who process them who are already overburdened.

"They essentially go through the same process for the fast tracked permits as the regular permits so there are some challenges there."

Sen. Burch said he spent time looking at the delays but all staff seemed to be working when he paid visits.

He said he was tempted to shut the whole Immigration Department down for a month to clear the arrears but recognised that couldn't be done.

"The other solution I think exists in a casual, ad hoc way and very sporadic is a nightshift. That may provide us with a very real solution if we formalise and expand it.

"It is very much processing paper."

He said work permit term limits had also caused further bottlenecks with employers leaving it late to prepare exemption applications.

"I can tell you there are boxes lined up outside.

"We will look at how we can accelerate that process. I am determined that any delays are not a result of there being a blockage at the Ministry."

Sen. Burch said he had met with all the employers' groups and will continue to do so to help reduce the backlog.