If the spouse of a non-resident files taxes, they 100% must declare the income of the non-resident spouse. Failure to do so is tax fraud. There are no taxes paid on it but most benefits/credits are based on family income and therefore require the entire family income, whether it was earned in Canada or not.
To be clear, the Canadian resident spouse ONLY needs to file a tax return IF the CRA rules require that spouse to file a return. Being married to a non-resident spouse is NOT something that triggers the requirement to file a return, REGARDLESS of the non-resident spouse's income.
And as I clearly stated, if the resident spouse does file a Canadian tax return, the resident spouse does not necessarily need to enter the non-resident spouse's income. (For example, the resident spouse can indicate the non-resident spouse's income is unknown and enter NO amount for this line in the tax return . . . which is NOT the same as entering zero.) BUT as I further noted, not including the non-resident spouse's income has consequences in terms of qualifying for credits/benefits.
In particular, if the Canadian resident spouse files a tax return and does NOT include the non-resident spouse's income that is NOT in itself tax fraud. (Contrary to misinformation commonly posted here by some forum-resident, self-appointed, unofficial, and often nowhere near accurate apparent
benefits-police.) Not including the non-resident's income at all simply precludes qualifying for those credits/benefits which depend on calculations taking into account both spouses' income.
Under-reporting, or purporting to include a spouse's income without actually disclosing the actual income, is DIFFERENT than overtly NOT reporting the spouse's income. Yes, that would be submitting false information. Submitting false information is tax fraud.
So sure, if a resident spouse submits a tax return PURPORTING to be eligible for certain credits/benefits or deductions, and PURPORTS to be reporting the non-resident's spouse income but does NOT actually report it, yeah, fraud. (Or misrepresents other material information, including by omission, that too would be fraud . . . such as dishonestly reporting marital status.)
But again, there is NO obligation to file a return at all UNLESS the resident-spouse is personally obligated to file a return . . . and the non-resident spouse's income is NOT something which triggers a resident spouse's obligation to file a return.
AND even if the resident spouse files a return, he or she can do so and elect to NOT include the non-resident spouse's income, recognizing this results in NOT being eligible for certain credits/benefits and deductions. That is NOT fraud.
As an aside, I realize that there is probably a significant amount of benefits fraud perpetrated by SOME immigrants. And some obtaining of benefits by those who do not actually qualify but who are not informed of the rules sufficiently.
But there is NO hint the query here in anyway was asking about how to get away with defrauding Canada Revenue or government benefit programs. The insinuations of fraud are gratuitous. Unwarranted.
The basic questions are NOT complicated, BUT who must file a return and what must be reported in the return are dictated by Canada Revenue and Tax law. NOT immigration law or immigration status. And
@Buletruck gets it right (well almost right):
If his spouse and children are in Canada, then he has significant residential ties in Canada and would be considered a resident for tax purposes. Being as that isn’t completely clear, I’d suggest you take the time to consult with a tax lawyer to clarify your status (depending on where your family is living).
https://www.canada.ca/en/revenue-agency/services/tax/international-non-residents/information-been-moved/determining-your-residency-status.html
I noted "almost right" since just because a non-resident has a spouse and dependent children in Canada does NOT, not in itself, make that individual a resident of Canada for tax-purposes . . . generally that alone will NOT make an individual a resident for tax purposes, and beyond that it can be a lot more complicated than that (and remember even if an individual meets certain criteria that would ordinarily make that person a resident of Canada for tax purposes, IF that individual is otherwise a resident for tax purposes of another country with which Canada has a treaty governing these matters, he or she might NOT be a resident of Canada for tax purposes, subject to the individual meeting all tax filing obligations otherwise, noting that there circumstances which require a non-resident to file a non-resident return, but also including meeting the tax filing obligations of the other tax treaty country, the latter being a requisite to qualify for non-resident of Canada for tax purposes).
Beyond that, as a general proposition (subject to applying the applicable rules to the particular facts in individual cases), persons asking for or otherwise receiving certain credits/benefits generally must meet all the rules for qualifying for those benefits, including filing accurate tax returns. BUT persons who are NOT asking for or receiving such credits/benefits do NOT need to file any return unless there are other rules pursuant to which they are required to file a return, AND even if they file a return they do NOT need to report a non-resident spouse's income.
Which leads back to the response by
@Buletruck referring to aspects of the OP's query not clearly showing just what the individual's residency status is, let alone other factors relevant to collateral issues, such as qualifying for this or that credit or benefit.
Blanket misstatements that a resident spouse must file a Canadian tax return AND report a non-resident spouse's worldwide income are all too common in this forum. IT depends. And it depends on a lot more than just marital status and immigration status. Perhaps discussions in the conference about Settlement Issues, at
https://www.canadavisa.com/canada-immigration-discussion-board/forums/settlement-issues.14/ , are more focused on such matters and include more accurate observations,
but QUALIFIED TAX PROFESSIONALS, or at least reputable sites where tax-related questions are more reliably discussed, are a FAR better source for questions about tax filing obligations, including issues like residency for taxation purposes, and especially questions about what information must be reported in a tax return. Particularly since this forum has been corrupted by more than its share of misinformation regarding these matters.