A tenants rights group is warning that backyard dumping will escalate if council chiefs get a user-pays plan wrong for Christchurch's kerbside collection.

The Christchurch City Council is surveying 16,000 residents for their thoughts on charges based on the size of rubbish, recycling and greens bins.

The plan is to reduce trash going into landfills with a separate charge instead of it being blended into landowners' rates bills.

Tenants Protection Agency manager Penny Arthur said even hard-up tenants had no objections with reducing rubbish, but this could become another expense.

She said serious thought was needed on who chose the bins and if the landlord or the tenant would end up paying the charges.

Arthur said this wouldn't work if a couple with four children had small bins because the landlords wanted to save costs.

"There's a risk that landlords face is if tenants can't afford the waste disposal do they end up collecting in the backyard,'' she said.

"In boarding houses which only have one red bin there might be six, seven, or eight people in one property and that's already causing problems.''

The group wants to know if renters still have to pay even if they don't put their bins out.

Resource recovery manager Ross Trotter said the survey results would give the council an understanding of how it could charge for different sized bin.

"We're looking to improve how we deliver our waste services. One thing we will be exploring is how we can respond to residents' calls for more choice in the size of bins they have, while still meeting our goal of changing our throw-away culture and reducing the amount of waste being disposed to landfill."

Christchurch Councillor Yani Johanson said a user-pay charge for the red, yellow and green bins made a lot more sense, as finding ways to reduce rubbish was important.

"If people wanted a smaller bin they could pay less and I think that's a better way to go than just giving people a one-size-fits-all and people paying the full price,'' he said.

The council says residents will be consulted later this year if the user-pays charge plan goes ahead.