Nearly half of Christchurch's recycling is going to landfill because it is contaminated with waste, including guns and dead animals.
During the level 4 lockdown when sorting recycling was not possible, the council allowed households to use their yellow recycle bins for general waste.
Eco-Central which is owned by Christchurch City Council deals with the city's recycling.
Compliance manager Averil Stevenson said in the 12 months before the lockdown, only three truckloads of recycling was sent to landfill - but now 42 percent is being thrown away.
"We are finding dead animals, chainsaws, nappies, guns and vacuum cleaners amongst other household items in the recycling bins."
The council has spent more than $1 million sending the contaminated recycling to landfill.
Stevenson said pre-Covid-19 the recycling plant was processing 200 tonnes a day and had 30 staff working 10 hour days.
"We were producing 20-40 containers a week of bailed material and selling it locally where we could, even then there was a marked increase in waste in the recycling."
With international markets closing mills, Eco Central stopped processing recycling on 1 April and didn't start again until 4 May.
"We haven't recovered since then and if anything we are going downhill," Stevenson said.
"Every load of recycling from Christchurch City Council bins comes to us and is tipped on the floor - staff look at it and assess the level of waste, if it's high the whole load is rejected."
She said international markets had reopened and were hungry for recycled material due to so many countries still being in lockdown.
"It's frustrating that there is a high need for good quality recycled material in the market and we are missing out on the opportunity to supply it," Stevenson said.
The council has teams out on the streets assessing bins and if someone is a repeat offender, they risk having their bin removed.