Non-compliance can result in prosecution with a fine of up to $600,000, Mr Peet said.
HDC environmental engineer Ryan Hughes said rather than appeal the abatement notice, HDC preferred to focus its resources on its current waste assessment process.
He said HDC would discuss having the notice cancelled with Horizons. HDC would continue to use the landfill.
HDC earns around $950,000 of its $2.1 million annual landfill income from taking Kapiti Coast District waste. Kapiti mayor K Gurunathan has suggested stopping Kapiti's waste going to the landfill.
He said he would expect Kapiti's contractor, MidWest Disposals Ltd, to abandon Hokio and truck Kapiti waste to a compliant landfill elsewhere.
"I'm putting Horowhenua District Council on notice with a warning.
Their communities and residents living around the Hokio landfill are demanding we stop dumping Kapiti rubbish in their neighbourhood," Mr Gurunathan said.
MidWest Disposals' co-owner Waste Management did not reply to queries before the Horowhenua Chronicle went to print.
Ngatokowaru marae is about 500m from the landfill.
Its environmental spokesperson, David Moore, said the smell had not decreased since the abatement notice was issued in July.
"It's very invasive and noxious, the most appalling smell. It destroys people's lifestyles and their pleasure of life," he said.
"The dump is a complete dog. It's a liability and long term it's an environmental time bomb. It is causing a public nuisance and gases are a health and safety issue.
"We're not surprised HDC dropped the appeal. It [appears] a delaying tactic during which they hoped to solve their odour problem, but it has got worse in that time," Mr Moore said.
Malcolm Hadlum, from environmental watchdog Neighbourhood Liaison Group, said the fine was inadequate.
"History shows that when HDC get caught polluting they get a slap on the wrist with a wet bus ticket, the lightest of penalties or none at all.
This agreement between the councils makes a mockery of the anti-pollution laws."