The federal government is taking aim at a series of recent decisions by a Nova Scotia judge to approve at least nine citizenship applications.

Government lawyers want the judge's decisions overturned and are urging the Federal Court to allow judicial reviews of the cases.They say the nine people seeking citizenship did not meet the residency requirements.

The cases involve Judge Ann Janega, who was appointed to the federal citizenship commission in December 2013 by Immigration Minister Chris Alexander.

The first case heard Wednesday involves a Nigerian airline pilot who settled with his family on Prince Edward Island in 2007 and applied for citizenship.

But when Akintomiya Oladapo Ojo made the application in 2013, he fell short of residency requirements. He needed to have spent three of the last four years in Canada, according to court documents.

Catch-22 job predicament

The pilot said he was working towards obtaining the Transport Canada airline pilot licence he needed to be able to work in Canada. While his family remained on P.E.I. (later moving to Calgary), Ojo spent 12-week stints in West Africa building up his flight hours.

Federal Court Justice Richard Mosley has reserved his decision on that case for a later date, but did express some sympathy for Ojo's job predicament.

At one point he called it a Catch-22 and asked the federal government's lawyer whether Ojo should instead take a job at McDonald's until he qualifies for citizenship.

Ojo, his family and their lawyer, Anthony Merah, appeared by teleconference from Calgary, where the family now lives.

Merah said Ojo has succeeded in getting a Canadian licence and is looking for work with a Canadian carrier.

He said the family sold everything they had in Nigeria in order to move to Canada. Ojo took contracts overseas so his children would not suffer a lesser lifestyle than they were used to.

Halifax immigration lawyer Lee Cohen says he's never seen so many cases presided over by one judge come under review at once. (CBC)

But federal lawyer Melissa Chan argued Ojo's citizenship application should not have been approved. She said the evidence before Janega did not support Ojo's citizenship and that he had spent less than half the time in Canada he needed to meet the residency threshold.

In a decision last November, Janega granted Ojo's application for citizenship, even though he had not spent the required amount of time in Canada.

"He has demonstrated that Canada is the place where the applicant 'regularly, normally or customarily lives' and has a centralized his mode of existence in Canada," she wrote.

Federal government intervention

The federal government disagrees with that assessment. It's also not the only case it is taking issue with.

This spring, lawyers with the Canadian Justice Department submitted applications to the Federal Court in a bid to overturn the decisions Janega made on eight citizenship applications over a five-week span, CBC News has learned.

Citizenship judges typically assess applications that are not clear-cut, and observers say it's fairly uncommon for federal lawyers to appeal such decisions.

A long-time Halifax immigration lawyer calls this review of so many cases decided by a single judge unusual.

"It's quite uncommon to see them clustered in a bunch and have a number of cases dealing with the same judge, over the same legal issue, go forward at the same time," said lawyer Lee Cohen.

"I have not seen a cluster of cases like this before. Cases are usually very spread out over the calendar, as they come in, as they get decided."

Few details have been filed in court about the eight applicants, but the federal government argues Janega based her decisions on "erroneous" findings of fact.

Upcoming changes

Under the current law, citizenship judges can, in certain circumstances, approve citizenship for immigrants who don't meet that threshold, but have a strong attachment to Canada.

Citizenship judges will soon lose some of their case-by-case discretion.

Under new rules coming into force on Thursday, the federal government lengthens residency requirements to four out of six years. It also defines that time as "physically present" in Canada.

In an email, a spokesman for Citizenship and Immigration Canada said the changes will help deter "citizens of convenience" who live most of the time outside the country, but still return to take advantage of government benefits.

The department also says it will help with the integration of immigrants.

Both Immigration and Justice departments declined comment on the cases currently before the courts.