
431 S.E.2d 485 (1993)
110 N.C. App. 817
In the Matter of Tammy RICHARD and Laura Richard, minor children, Celeste Rast, Guardian Ad Litem, Petitioners,
v.
Rosemary Lee MICHNA (a/k/a Rosemary Kwiatkowski) and Rene Paul Richard, Respondents.
No. 9228DC662.
Court of Appeals of North Carolina.
July 6, 1993.
*487 Barry L. Master, and Charlotte A. Wade, Asheville, for petitioners-appellees.
Kathy A. Gleason, and Susan C. Lewis, Asheville, for respondents-appellants.
WELLS, Judge.
Appellant's first assignment of error is a generalized, non-specific statement that the trial court erred in entering judgment terminating her parental rights. Pursuant to this "broadside" assignment, appellant asserts for the first time on appeal that she was denied due process because she was not appointed a guardian ad litem, citing and relying on the provision of N.C.Gen.Stat. § 7A-289.23. We find, without addressing respondent's due process objection, that G.S. § 7A-289.23 mandates the appointment of a guardian ad litem and requires reversal on this basis alone.
N.C.Gen.Stat. § 7A-289.23 provides as follows:
The court shall have jurisdiction to terminate the parental rights of any parent irrespective of the age of the parent. The parent has the right to counsel and to appointed counsel in cases of indigency *488 unless the parent waives the right.... In addition to the right to appointed counsel ... a guardian ad litem shall be appointed in accordance with the provisions of G.S. 1A-1, Rule 17, to represent a parent in the following cases:
(1) Where it is alleged that a parent's rights should be terminated pursuant to G.S. 7A-289.32(7)
G.S. § 7A-289.32(7) permits a court to terminate parental rights where "the parent is incapable as a result of mental retardation, mental illness, organic brain syndrome, or any other degenerative mental condition of providing for the proper care and supervision of the child...." Here, the petitioner alleged and the trial court found, inter alia, the respondent mother was incapable, because of mental retardation and other mental conditions, of proper care and supervision of her children. Respondent mother had a right to a guardian ad litem under these circumstances; however, a review of the record indicates that the respondent mother never petitioned the trial court to appoint a guardian ad litem, nor did she object to the failure to have one appointed at trial. In short the issue was never presented at the trial court level.
The question before us now is whether respondent mother's right to a guardian ad litem under these circumstances may be waived by failure to assert that right at trial. We note initially that this is a case of apparent first impression in this State, inasmuch as we have been unable to locate published opinions dealing with this precise issue involving G.S. § 7A-289.23.
Instead, we rely on the well established law regarding waiver of a statutory or constitutional right. The general rule, set forth in In re Bullabough, 89 N.C.App. 171, 365 S.E.2d 642 (1988), is that failure to assert a statutory or constitutional right in the trial court is a waiver of that right. See also State v. Gaiten, 277 N.C. 236, 176 S.E.2d 778 (1970). This broadly stated rule does not hold, however, where the statute in question is expressly mandatory in nature. The North Carolina Supreme Court shed light on this exception.
When a trial court acts contrary to a statutory mandate, the error ordinarily is not waived by the defendant's failure to object at trial. We also have recognized that a trial court sometimes has a duty to act sua sponte to avoid statutory violations; for example, the trial court must exclude evidence rendered incompetent by statute, even in the absence of an objection by the defendant.
State v. Hucks, 323 N.C. 574, 374 S.E.2d 240 (1988) (citations omitted). The court further noted that this exception does not apply where a statute requires a motion by the defendant before he is entitled to the rights it guarantees or where the trial court is only required to act when prompted to do so by the litigants. In such cases, the general rule of waiver adheres.
G.S. § 7A-289.23 is clearly mandatory, and its mandate is directed to the trial court. It expressly requires that a guardian ad litem "shall be appointed" whenever the petitioner alleges, as it did here, that parental rights should be terminated because the parent is incapable of proper care and supervision of the children due to mental retardation or other mental condition. Under G.S. § 1A-1, Rule 17, only the trial court has the authority to make the appointment of the guardian ad litem. The statute does not require, nor does it imply, that it is the respondent's responsibility to ask for the appointment of the guardian ad litem. See Hucks, supra.
While inclined to note that we do not believe respondent mother has in any way been prejudiced by this error, in keeping with the clear import of Hucks, we are persuaded that the mandate of the statute must be observed, and a guardian ad litem must be appointed.
We therefore remand this case for a new trial with a guardian ad litem to be promptly appointed for the respondent mother to accommodate the statutory requirement of G.S. § 7A-289.23. In so doing, it appears obvious to us that the children should remain in the physical custody of the Department of Social Services pending further adjudication, due to the aggravated circumstances and evidence of abuse in this case. *489 The portion of the trial court's order terminating the parental rights of the respondent father, not having appealed in this action, remains undisturbed.
Reversed and remanded for a new trial.
COZORT and JOHN, JJ., concur.
