Sam Bracanov, a 76-year-old with a history of protest against the British royal family, pleaded not guilty to preparing to commit a crime, a day after he was arrested in Auckland. The royal couple had not yet arrived in New Zealand's largest city.
Bracanov was ordered to stay at least 500 metres away from the couple as part of his bail conditions. He was ordered to reappear at the Auckland District Court later this month.
Sitting outside the courthouse, Bracanov said he would have thrown the manure at Charles, the longest-serving heir to the British throne, and his wife had he not been arrested.
"I make it liquid like porridge," he told reporters. "I would have done it."
Bracanov has used sweeter-smelling ways to express his anti-royalist feelings in the past. He was convicted and fined for spraying air fresheners at Prince Charles to "remove the stink of royalty" during a previous visit to Auckland in 1994.
A smattering of anti-royalists have heckled the royal couple during their six-day visit to New Zealand. Others have been miffed by Prime Minister John Key's confirmation that New Zealand, a member of the British Commonwealth, would foot the bill for Camilla's travelling hairdresser.
But New Zealanders are generally staunch supporters of the monarchy.
A poll conducted by Television New Zealand before the royal couple arrived last week showed 70pc of respondents want to keep Queen Elizabeth as head of state.
Prince Charles and Camilla have been touring Australia and New Zealand as part of the celebrations to mark Queen Elizabeth's 60 years on the throne.