Benjamin Glynn, 39, allegedly believes masks are pointless and do not protect people from contracting Covid-19.
A British man arrested for refusing to wear a facemask on Singapore's subway has been detained in a mental hospital after branding legal action against him "disgusting".
As his trial began on Thursday, 39-year-old Benjamin Glynn said he would "never plead guilty or not guilty" to the charges against him.
"I refuse to be a slave," he added as anti-mask supporters backed him from the public gallery.
"I think it's insane that I am facing a trial at all, just for not wearing a mask."
Glynn, from Yorkshire, had his £2,700 (NZ$5330) bail revoked on July 19 after originally being arrested for his refusal to wear a mask on May 7. He faces additional charges for failing to wear his mask at a court appearance in July.
The court was urged to assess the married father of two's mental state by Timotheus Koh, the deputy public prosecutor, who said Glynn's family described a "marked change" in his actions since the pandemic began.
"The accused's behaviour in court speaks for itself," Koh said.
But Glynn replied in a raised voice: "My mind is crystal clear. I'm wide awake. I'm enlightened."
He claimed he was "sovereign" throughout the trial, adding "the charges don't apply to me".
Glynn has worked in Singapore since 2017 as the employee of a British company based in the country.
He was recorded breaking Singapore's strict mask-wearing mandate before officers tracked him down after the clip went viral. The defendant said his family had since returned to their home in Leeds without him.
"I want to leave the country anyway - just let me go," he said.
Previously unrepresented, the Glynn referred to Abdul Rashid Abdul Rahman, who was originally his bailor, as his "legal counsel". But District Judge Eddy Tham banned Rahman from representing Glynn because he was not legally qualified.
Judge Tham ordered Glynn to be remanded to the Institute of Mental Health for psychiatric monitoring until the trial continues on August 19.
As he was led away the defendant shouted that the police had hunted him down "like a pack of animals" and that the decision "is not justice".
The charges against Glynn include three offences - two counts of harassment and being a public nuisance - under the Covid-19 (Temporary Measures) Act. A fourth charge relates to his decision to forgo a mask outside the court building.
The charge of harassment comes with a maximum jail term of a year and a fine of up to $5131, while conviction for breaching the Covid-19 rules could result in a six month sentence and $10,400 fine.