The Court of Appeal has powers to take receive evidence under s. 683. This consists of the authority to:
- order the production of any writing, exhibit or other thing connected with the proceedings;
- "order any witness ... to attend and be examined before the court of appeal..." and admit the testimony as evidence;
- order an inquiry and report to a special commissioner and to act on such a report.
Powers of court of appeal
683. (1) For the purposes of an appeal under this Part, the court of appeal may, where it considers it in the interests of justice,
- (a) order the production of any writing, exhibit or other thing connected with the proceedings;
- (b) order any witness who would have been a compellable witness at the trial, whether or not he was called at the trial,
- (i) to attend and be examined before the court of appeal, or
- (ii) to be examined in the manner provided by rules of court before a judge of the court of appeal, or before any officer of the court of appeal or justice of the peace or other person appointed by the court of appeal for the purpose;
- (c) admit, as evidence, an examination that is taken under subparagraph (b)(ii);
- (d) receive the evidence, if tendered, of any witness, including the appellant, who is a competent but not compellable witness;
- (e) order that any question arising on the appeal that
- (i) involves prolonged examination of writings or accounts, or scientific or local investigation, and
- (ii) cannot in the opinion of the court of appeal conveniently be inquired into before the court of appeal,
be referred for inquiry and report, in the manner provided by rules of court, to a special commissioner appointed by the court of appeal;
- (f) act on the report of a commissioner who is appointed under paragraph (e) in so far as the court of appeal thinks fit to do so; and
- (g) amend the indictment, unless it is of the opinion that the accused has been misled or prejudiced in his defence or appeal.
Parties entitled to adduce evidence and be heard
(2) In proceedings under this section, the parties or their counsel are entitled to examine or cross-examine witnesses and, in an inquiry under paragraph (1)(e), are entitled to be present during the inquiry, to adduce evidence and to be heard.
R.S., 1985, c. C-46, s. 683; R.S., 1985, c. 27 (1st Supp.), s. 144, c. 23 (4th Supp.), s. 5; 1995, c. 22, s. 10; 1997, c. 18, ss. 97, 141; 1999, c. 25, s. 15(Preamble); 2002, c. 13, s. 67; 2008, c. 18, s. 29.
- s. 683 was previously s. 610, R.S.C. 1970, c. C-34. see Table of Concordance (Criminal Code)
The test for the admission of fresh evidence is set out as follows: 
- The evidence should generally not be admitted if, by due diligence, it could have been adduced at trial provided that this general principle will not be applied as strictly in a criminal case as in civil cases
- The evidence must be relevant in the sense that it bears upon a decisive or potentially decisive issue in the trial.
- The evidence must be credible in the sense that it is reasonably capable of belief, and
- It must be such that if believed it could reasonably, when taken with the other evidence adduced at trial, be expected to have affected the result.
Where however, the application arises out of the Crown's failure to provide disclosure, then test is less onerous. The accused must show that his right to make full answer and defence was violated by showing either "that there is a reasonable possibility the non-disclosure affected the outcome at trial" or that it affected "the overall fairness of the trial process".
The Palmer criteria are somewhat relaxed when the issue concerns the integrity of the trial process.
The due diligence criteria is to be applied flexibly when there is a risk of a miscarriage of justice. 
R v Palmer, 1979 CanLII 8 (SCC),  1 SCR 759, at p. 775
R v Levesque, 2000 SCC 47 (CanLII)
R v Hay, 2013 SCC 61 (CanLII) at para 63
R v McQuaid, (sub nom R v Dixon), 1998 CanLII 805 (SCC),  1 SCR 244 at 34
R v Taillefer, 2003 SCC 70 (CanLII),  3 SCR 307
R v Illes, 2008 SCC 57 (CanLII),  3 SCR 134 at para 24
- R v Dixon at para 34
R v Benham, 2013 BCCA 276 (CanLII) at para 33
R v Dunbar, 2003 BCCA 667 (CanLII) at paras 33–37
- R v Fraser, 2011 NSCA 70 (CanLII) at para 36
The courts are reluctant to consider fresh evidence on appeal as it is outside of the appeal court's role.
There are four criteria to consider before allowing the evidence:
- The evidence should generally not be admitted if, by due diligence, it could have been adduced at trial provided that this general principle will not be applied as strictly in a criminal case as in civil cases.
- The evidence must be relevant in the sense that it bears upon a decisive or potentially decisive issue relating to the sentence.
- The evidence must be credible in the sense that it is reasonably capable of belief.
- The evidence must be such that if believed it could reasonably, when taken with the other evidence adduced at trial, be expected to have affected the result.
See also:R v Power, 2011 NLCA 68 (CanLII)
- R v Lévesque, 2000 SCC 47 (CanLII) at para 20
- Levesque, at 35
The Court of Appeal has jurisdiction to order a post-sentence report under s. 687 or 721. If it to be ordered under s. 721, the order should only be made once the court has received some evidence, such as by affidavit, establishing the basis for ordering the report.
Where the ordering of a post-sentence report is in dispute the proper test is the same as for the admission of fresh evidence.