If you owe money to any of the tax authorities because you failed to file a return for one or more years, you can make a voluntary disclosure. You will pay only the tax due plus interest. No penalties will be assessed. You have to make a complete disclosure. The information can be less than or more than a year old. Plus you must contact the Canada  Revenue Agency prior to the start of an investigation or an audit.

Typical voluntary disclosures include; domestic business income never reported, failure to collect or remit GST/HST and/or source deductions, information returns not previously submitted, foreign wages and benefits not reported, and domestic and foreign dividends and interest never reported.

Relief is determined on a case by case basis.