The lawyer for two of Kim Dotcom's Megaupload associates is trying to convince a High Court judge to allow his clients to stay in New Zealand.
Grant Illingworth, QC, lawyer of Mathias Ortmann and Bram van der Kolk, who are appealing their extradition to the United States, says his clients have not been properly heard in court.
Illingworth said his clients have not had a fair hearing - despite last year's 10-week District Court trial.
Mr Illingworth believes the District Court judge did not follow due process, in allowing the pair a proper defence.
He told Auckland's High Court today that the District Court judge disallowed their witnesses, and did not give reason as to why that was the case before ordering the extradition of Dotcom and his associates in December.
"This is a serious, serious breach of judges duties... and that alone is a matter that should cause concern," said Illingworth. "Something has gone seriously wrong in this process."
The United States wants them extradited, so it can pursue its own case against four men involved in the multi-million dollar Megaupload website.
Illingworth argues the arrest of his clients was done amidst unlawful spying by the police, the GCSB and the United States' five eyes network.
He says warrants for his clients' arrests, and the seizure of all of their assets was granted outside of usual police process - and all of this was covered up by the same authorities in the District Court extradition trial.
Illingworth wants his clients to at the very least, be able to use their own money to fund a proper defence in a New Zealand court, before a decision is made about whether they can fairly be extradited to the United States.
In December, a judge ruled there was "overwhelming" evidence 42-year-old tech entrepreneur Dotcom and his three co-accused - Ortmann, Finn Batato and Van der Kolk - had criminal charges to face in the US over their part in running file-sharing website Megaupload.
But their lawyers immediately filed an appeal and the High Court at Auckland is today beginning to hear arguments about why the extradition shoudn't go ahead. The hearing is set down for six weeks.
During the 10-week extradition hearing last year, lawyers for the US argued Dotcom and his associates had earned US$175 million ($242m) by running a website funded largely by revenue from publishing copyright-infringing files. They said the site had paid people to illegally upload copyright-infringing files and then charged others to watch them.
But Dotcom's lawyer, Ron Mansfield, said the website was protected by a "dual- use" defence - where a company couldn't be responsible for the illegal use of products with other legitimate purposes.
The High Court ruling is unlikely to be the end of the story though, with both parties open to appealing and Dotcom saying he would take the case all the way to the Supreme Court if it didn't go his way. His legal team has already made two unsuccessful trips to the Supreme Court as part of a protracted legal battle since he was arrested.
The four men have been locked in a protracted legal battle over the case since Dotcom was dramatically arrested in a Hollywood-style raid on his Coatesville mansion in 2012.
They face charges of conspiracy to commit racketeering, conspiracy to commit money laundering, wire fraud and two kinds of criminal copyright infringement based on an FBI investigation going back to 2010. If eventually extradited and found guilty in the US, they could be up for decades in jail.
