A lone picketer outside Police National Headquarters in Wellington, two days after four police officers were shot in the Bay of Plenty.

A lone protester has picketed Police National Headquarters lamenting the fact more police weren't shot in the Kawerau siege.

The unidentified man sat on a low wall directly opposite police headquarters on Molesworth St in Wellington on Friday.

His sign read: "Only four shot not enough."

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On Wednesday near Kawerau, in eastern Bay of Plenty, four police officers were shot and injured during a cannabis operation in the region.

After an overnight siege of the rural house where the shots had been fired, the alleged gunman 27-year-old Rhys Warren was arrested.

On Thursday, Warren appeared in the Whakatane District Court where he faced four charges of using a firearm against a law enforcement officer.

A police spokesman said the protester's actions were disappointing.

"We recognise people's rights [to protest] but find it hugely disappointing given the circumstances and considering what police do on behalf of the community."

Of the four officers who were shot, one was shot in the head and another in the hand.

They were pulled to safety by their colleagues before being taken to hospital in rescue helicopters.

Almost 24 hours after the incident had begun, Warren was arrested and taken into custody "without incident", according to police.