The right for an accused to retain counsel of his choice is recognized by section 10(b) of the charter and upheld in the Supreme Court Case of R. v. Willier, 2010 SCC 37.
Most cases relating to the right to retain counsel of choice deals with the initial duties of the police in informing a detainee of their charter rights, however, turning to the law both in criminal and civil cases we can see that the only limitations on the right to retain counsel of choice are as follows:
1. The accused must be reasonably diligent in attempting to obtain counsel if he wishes to do so. If the accused person is not diligent in this regard, then the correlative duties imposed upon the police to refrain from questioning the accused are suspended: see R. v. Tremblay,  2 S.C.R. 435.
Such a limit on the rights of a detainee are necessary, as Lamer J., as he then was, noted in Smith, "because without it, it would be possible to delay needlessly and with impunity an investigation and even, in certain cases, to allow for an essential piece of evidence to be lost, destroyed or rendered impossible to obtain. The rights set out in the Charter, and in particular the right to retain and instruct counsel, are not absolute and unlimited rights. They must be exercised in a way that is reconcilable with the needs of society" (p. 385).
2. A litigant’s right to retain counsel of his choice is not an absolute right but, rather, it is subject to reasonable limits. In his view, the court has a duty not only to the parties to the litigation but also to the public "to ensure that lawyers observe the highest standards of professional conduct with respect to cases before the court". Where those high standards are not observed, the Court has jurisdiction to intervene and remove a lawyer from the record. In granting the order requested, the motions judge applied the principles enunciated by Jewers J. in Morton v. Asper (1987), 49 Man. R. (2d) 167 (Q.B.), aff'd (1987), 51 Man. R. (2d) 207 (C.A.).
Otherwise there are no restrictions to the right of an accused or litigant to retain counsel of his choice.