Canadian government lawyers on Wednesday laid out a case for extraditing a senior Huawei executive to the United States, saying it is based on "a fraud on a bank."

The US alleges Meng Wanzhou, the chief financial officer of tech giant Huawei, lied to the bank HSBC about Huawei's relationship with its Iran-based affiliate Skycom, putting the bank at risk of violating US sanctions against Tehran.

Meng has denied the allegations.

"Fraud is at the heart of this case," Crown counsel Robert Frater told the court.

"Lying to a bank to obtain financial services is fraud," he said. "The defense has said this is a case about sanctions, but this is unsupported by case law."

In order to win extradition, lawyers for Canada's attorney general on behalf of the US Justice Department must demonstrate that the US accusations against Meng would be considered a crime in Canada if they'd occurred here. This is a key test referred to as double criminality.

In court documents, the Crown said the "essense" of Meng's actions amounted to "fraud on a bank," saying she made "several misrepresentations to a bank to secure financial services."

They assert that Huawei controlled the operations of Skycom in Iran; that its staff used Huawei email accounts and security badges; and its bank accounts were controlled by Huawei.

Meng, however, told HSBC executives in a presentation in 2013 that Huawei no longer owned Skycom and that she had resigned from that company's board.

From 2010 to 2014, meanwhile, HSBC and its American subsidiary cleared more than US$100 million worth of transactions related to Skycom through the US.

"Simply put, there is evidence she deceived HSBC in order to induce it to continue to provide banking services to Huawei," the Canadian justice department said in court filings.

The defense has argued that Canada has "expressly repudiated" US banking sanctions against Iran that underpin the extradition case.

Were Canada to agree to Meng's extradition, defense lawyer Eric Gottardi said earlier this week, "we would be allowing a foreign state to criminalize conduct in Canada" that is not illegal in this country.

Meng's arrest during a stopover of a Hong Kong-to-Mexico flight in December 2018 caused a major rift in Canada's relations with Beijing, which followed up by detaining two Canadians and restricting Canadian agricultural imports.

The arrests on espionage suspicions of former diplomat Michael Kovrig and businessman Michael Spavor have been widely interpreted as retribution by Beijing aimed at pressuring Canada to free Meng.

While Meng is out on bail, the two Canadians remain in China's opaque penal system.