Pikangikum First Nation v. Nault, 2012 ONCA 705 has a good summary of the law related to the tort of misfeasance in a public office:
 In Odhavji Estate v. Woodhouse, 2003 SCC 69,  3 S.C.R. 263, at para. 23, Iacobucci J., writing for a unanimous Supreme Court explained that the tort of misfeasance in public office has two elements:
(1) The defendant must have engaged in deliberate and unlawful conduct in his or her capacity as a public officer; and
(2) The defendant must have known that the conduct was unlawful and that it was likely to harm the plaintiff.
 At para. 24, Iacobucci J. set out the distinction between acts and omissions for purposes of the tort: "[A] failure to act can amount to misfeasance in a public office, but only in those circumstances in which the public officer is under a legal obligation to act."
 He went on to explain, at para. 25, that in the context of this particular tort, "misconduct" means: (i) an intentional illegal act (or, where there is a duty to act, an intentional omission); and (ii) an intent to harm an individual or class of individuals.
 He summed up the legal principle this way, at para. 28:
The requirement that the defendant must have been aware that his or her conduct was unlawful reflects the well-established principle that misfeasance in a public office requires an element of "bad faith" or "dishonesty". In a democracy, public officers must retain the authority to make decisions that, where appropriate, are adverse to the interests of certain citizens. Knowledge of harm is thus an insufficient basis on which to conclude that the defendant has acted in bad faith or dishonestly. A public officer may in good faith make a decision that she or he knows to be adverse to interests of certain members of the public. In order for the conduct to fall within the scope of the tort, the officer must deliberately engage in conduct that he or she knows to be inconsistent with the obligations of the office.