OTTAWA -- A letter sent by a Canadian immigration officer to a couple questioning the legitimacy of their marriage includes language that an NDP MP says is "offensive and insulting."

Federal NDP immigration critic Jenny Kwan has asked Immigration Minister Ahmed Hussen to look into what she calls a systemic problem with the way Hussen's department is treating applications under the spousal sponsorship program.

"To me, it's completely inappropriate and I think it's offensive and insulting," Kwan said.

"I would like for the government to look at the systemic issue of this letter and why such letters are being sent out through those spousal sponsorship applications."

The letter, from a Canadian immigration officer based in London, England, to a female applicant from Pakistan, says her permanent residency application appears suspect for a number of reasons -- including that she is three years older than her husband, a Canadian citizen who has lived in Canada since 2005.

"You and your sponsor (husband) do not appear well matched," the letter states, a copy of which was provided to The Canadian Press.

"You are three years older than him, he comes from a town four hours from where you live and you are not related, so it is unclear to me why the match was made."

It is unusual for Pakistani men to marry older women, especially if they are not related, the unnamed immigration officer writes. The officer also notes their wedding guest list of 123 people was small compared to traditional Pakistani weddings.

"This apparent deviation from the cultural norm raises concerns that your wedding may have taken place in order for you to gain permanent residence in Canada."

Kwan said she followed up with the department, only to find letters with such language are routinely sent to spousal sponsorship applicants from Pakistan to "'tease out a response."'

"Who are they judge whether or not that marriage is well-matched?" Kwan said.

"It's one thing to say, 'I do not believe in the authenticity of this marriage,' it's another to make a judgment on the quality of the marriage.... I find that offensive."

Kwan raised the issue in question period this week and again with Hussen during a Commons committee meeting Thursday, asking for the government to review its treatment of spousal applicants.

Prime Minister Justin Trudeau defended the program during question period, saying he was pleased his government has reduced a backlog of applications under spousal sponsorship and has also reduced waiting times from two years to 12 months.

"We also know there is more to do," Trudeau said.

Improvements to the program have been made, and scrutinizing spousal sponsorship applications is an important part of the work of his department, Hussen added.

"Our department continues to uphold measures to safeguard against marriage fraud and other program integrity risks."

Indeed, it's not uncommon for the immigration minister to become involved in cases involving spousal sponsorship that go before the courts.

Last week, a Federal Court judge rejected a judicial review application from Hussen's office in a spousal case that was initially rejected and then won on appeal. The office felt there was evidence contradicting the wife's claim that her marriage to a Nigerian man in 2014 was legitimate.