NSW Police set up an emergency operations centre at Menindee on Saturday after the waters were blanketed with fish and footage of the environmental tragedy went all over the world.

Contractors - many who worked on the clean-up after the 2018 and 2019 fish kills at Menindee - will lead the removal while police are working with a number of other agencies to ensure those in the remote town have access to clean drinking water.

Speaking at Dubbo Police Station on Monday afternoon, Western Region Commander Brett Greentree said all those involved in the clean-up faced an almighty challenge.

"Our objectives really are to ensure the town of Menindee has safe water to drink in the township and, secondly, the removal of the fish in an appropriate way. That's our two priorities," he said.

"There has been similar incidents in 2018 and 2019 but that's where similarities stop in terms of numbers.

"This is unprecedented in terms of the number of fish that have died as a result of toxic blackwater, which is a natural-occurring phenomenon from what I've been told."

The fish deaths have been attributed to hypoxic blackwater, a naturally occurring phenomenon that causes extremely low dissolved oxygen levels.

Commander Greentree was keen to stress the police have no expertise in what has happened in the water but added the possibility of more fish dying could not be ruled out.

As of Monday afternoon, Menindee's drinking water that comes through the water treatment plant remains safe to drink.

The concern is around those who use river water but a program put in place during the recent floods which devastated the Menindee region remains in effect.

"The water supply which is via the treatment works in Menindee is monitored 24/7. I can confirm at this point in time the water quality for the township is high quality and there has been no complaints whatsoever in regards to water quality," Commander Greentree said.

"I need to differentiate, of course, the river water is a different story and for those who rely on river water the council has arranged portable water to be delivered. That is something that has been in place during the floods when there has been issues in water supply. That is ongoing."

While there are plans in place for the water quality side of the response, the clean-up is a different challenge.

The contractors tasked with removing the fish hadn't arrived at the time of Commander Greentree's comments on Monday and a timeline on when cleaning would begin had not been set.

"I anticipate it will be this week and obviously for the people of Menindee I want it to be sooner rather than later so we're working hard to negotiate that and get the contractors in," he said.

The immediate focus of the clean-up will be around the town water supply areas of the river and those which are most filled with dead fish.

Commander Greentree added the process was not as simple as "scooping out the fish and burying them" and they would be relying on the experts.

"I'm certainly not making promises all the millions of fish will be removed by contractors because it really is a logistical nightmare," he said.

"But what we will be doing, via a risk assessment, is prioritising those high density areas and around the water supply."

The Menindee community will have the chance to ask questions of the police and representatives from Water NSW, Department of Planning and Environment, the Department of Primary Industries, NSW Health others at a community meeting in the town on Tuesday.

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Given all the town has been through in recent years with repeated fish kills, droughts and more recently floods, Commander Greentree added keeping people informed and progressing as quickly as possible was a major focus.

"I'm here at Dubbo at the moment so I can only appreciate and acknowledge the hardship and the smell the poor residents have to put up with," he said.

"It's really difficult after they went through a period of drought and floods and I acknowledge that.

"I think that is one of the reasons we, as an emergency operations centre, want to move this into gear very quickly and get some respite into the town as soon as we can.

"Unfortunately, we need to be really honest, and it's not a really quick fix where we can do it in 24 hours."

It is hoped another update in regards to when the clean-up can begin will be given at that meeting.