Wellington Water says its unclear when their Moa Point treatment plant will be fully-operational again

Remediation works are currently underway, focused on boosting wastewater flow through the city's long outfall pipe.

Warnings have been issued of more odour, and plume about one-kilometre from the coast.

Wellington Water Chair Nick Leggett, says they're working to stop the smell and sewerage from spreading further.

He says they then have to assess equipment, and fit new machinery to get the premises running.