Section 19 of the Federal Child Support Guidelines, provides that a court may impute income to a parent or spouse as it considers appropriate in the circumstances, which include:
(a) the parent or spouse is intentionally under-employed or unemployed, other than where the under-employment or unemployment is required by the needs of any child or by the reasonable educational or health needs of the parent or spouse;
(b) the parent or spouse is exempt from paying federal or provincial income tax;
(c) the parent or spouse lives in a country that has effective rates of income tax that are significantly lower than those in Canada;
(d) it appears that income has been diverted which would affect the level of child support to be determined under these guidelines;
(e) the parent’s or spouse’s property is not reasonably utilized to generate income;
(f) the parent or spouse has failed to provide income information when under a legal obligation to do so;
(g) the parent or spouse unreasonably deducts expenses from income;
(h) the parent or spouse derives a significant portion of income from dividends, capital gains or other sources that are taxed at a lower rate than employment or business income or that are exempt from tax; and
(i) the parent or spouse is a beneficiary under a trust and is or will be in receipt of income or other benefits from the trust.
http://www.canlii.org/en/ca/laws/regu/sor-97-175/latest/sor-97-175.html#sec19_smooth