Meng -- whose father is Huawei founder and CEO Ren Zhengfei -- has been in a two-year battle against extradition over charges the firm violated US sanctions on Iran.
She is accused of defrauding HSBC by falsely misrepresenting links between Huawei and its Skycom subsidiary, putting the bank at risk of violating sanctions against Tehran as it continued to clear US dollar transactions for Huawei.
Lawyers for Meng, 49, believe the affidavits could show the banking giant was aware of the links between Huawei and Skycom, which sold telecom equipment to Iran.
The evidence would help demonstrate the prosecution case was "manifestly unreliable," according to the lawyers.
In a decision released late Friday, Associate Chief Justice Heather Holmes of the Supreme Court of British Columbia ruled that the testimony requested by Meng's defense "relates to issues properly within the domain of a trial, not the extradition hearing."
Holmes said it was not for her to rule on issues of credibility in an extradition hearing.
"The proposed evidence could do no more than offer an alternative narrative from that set out" by the United States in its case against Meng, Holmes wrote.
"These would take the extradition hearing beyond its proper scope."
Last week, Huawei confirmed that Meng was taking HSBC to court in Hong Kong to access banking records she says will help her battle extradition.
In February, she lost a similar legal bid in London.
Meng's extradition battle in Vancouver has entered its final phase. Hearings resume on Monday and are expected to end in mid-May, barring appeals.
Washington has accused Huawei of stealing American trade secrets and banned US semiconductor chip makers from selling to it.
The case has caused a major diplomatic rift between Canada and China.
Meng was arrested on a US warrant during a Vancouver stopover in December 2018 and is being held under house arrest at her Vancouver mansion.
Two Canadians -- former diplomat Michael Kovrig and businessman Michael Spavor -- were detained in China days later in apparent retaliation for Meng's arrest. The pair have since had virtually no contact with the outside world. - AFP