The price fall was detailed by financial services company CoreLogic in its June report on housing markets.

Many people believe local housing and property values have fallen much further since the extent of PFAS chemical contamination became apparent from late 2016.

Katherine Times has been supplied one local real estate firm's advice to clients saying the local residential market was between 10-30 per cent down on prices recorded in 2014-15.

Some properties neighbouring the base are considered "unsaleable", a Senate hearing was told in Katherine last year.

CoreLogic says Darwin's property price falls are nine per cent in the past year but almost 30 per cent since 2017.

Alice Springs fell 8.2 per cent in the past year, CoreLogic says.

NT Opposition leader Gary Higgins said: "Today's news of house prices in Katherine falling 16 per cent is heart breaking but not surprising considering the economic and fiscal crisis we're experiencing under an out of control Gunner Government.

"Katherine's residents are struggling with a cut to housing subsidies for teachers, the Territory's construction sector has halved, there are no major projects on the horizon, NT bankruptcies are up 67 per cent in the last year alone and retail trade growth has been down since Labor came to government."

This all happens as Katherine properties are being officially revalued.

And rates are continuing to rise faster than most other areas of a depressed NT.

Many people expect their property prices to be very different from the values placed on them three years ago thanks to PFAS contamination of the region.

The fall in property values because of PFAS is the basis for a class action involving many hundreds of Katherine residents against the Department of Defence.

The Tindal RAAF Base caused the contamination.

Residents have faced a series of rate rises in recent years as the council tries to build its bank balance to pay for the replacement of the town's rubbish tip which some estimates place at costing $40 million - to close the current waste management facility and re-open a new one.

The general rate is to rise 7.5 per cent in the next year.

Council chief executive Rob Jennings insists Katherine's rates remain lower than anyone else outside Darwin.

Katherine's official property valuations are recalculated every three years by the Valuer General which is part of the Department of Infrastructure, Planning and Logistics.

Katherine's properties are to be revalued this year as at July 1.

But the revaluation will be too late for this year's rates, which will be set again on the old pre-PFAS values.

Unimproved Capital Value (UCV) identifies the amount land alone would be expected to sell for without any encumbrances or improvements (i.e. dwellings, sheds, pools etc.), a departmental spokeswoman has said.

"UCVs are determined by considering similar sales in the market, observed trends, supply and demand, and the land's current use and zoning.

"The 2019 Katherine revaluation will include analysis of sales prices that occurred within the Katherine locality between 2016 and 2019," the department said.

The department is conducting sales inspections from this month until September.

"In late October 2019 Notices of Valuation will be sent to land owners in the Katherine municipality," the spokeswoman said.

"In late November 2019 when the objection period has closed, a copy of the Valuation Roll will be delivered to council. Council will then use the 2019 Valuation Roll to apportion rates for the 2020 financial year."

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