Police and emergency services were called to the Big4 caravan park on Nailor Street in Hay at about 12pm on Monday.

A cleaner and a park staff member, females aged 34 and 43, entered one of the cabins and came across an unknown substance while cleaning and became ill.

The two workers were released from hospital on Tuesday as specialist police travelled to Hay from Sydney to carry out tests on the substance.

Murrumbidgee Police District Acting Inspector Andrew Papallo said on Wednesday that the test results had come in.

"At about 4pm [Tuesday] afternoon we had some guys from the drug squad in Sydney come up. They went into the cabin, they sampled the powder and it was found to be an inert substance," he said.

"There's no risk to anyone's health or safety so we released the cabin back to the caravan park so they can start cleaning everything up.

"We are continuing investigations and following up with NSW Health on the toxicology tests on the two females who were sick to see what happened to them."

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Inspector Papallo said police had spoken to the cabin's previous guests.

"[The guests] told us it was just some powder the used for medical purposes," Andrew Papallo said.

"The staff at the caravan park were great, they were very helpful throughout the entire process."

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