The minister said he believed OPA 4 could be mined in an "environmentally friendly" way while benefiting the Lightning Ridge area.

"The onus is on you ... it is up to you to prove me correct" was the warning given by the minister to the miners of Lightning Ridge as he made his announcement at the 4th National Opal Symposium.

Mr Hickey was in Lightning Ridge to officially open the symposium and said the decision on the establishment of the new Opal Prospecting Area under the provisions of the Mining Act had been reached only after exhaustive studies had taken place.

"A major environmental study commissioned by the Government over the Narran-Warrambool Mining Reserve at Lightning Ridge provided key environmental information to help manage future development of opal mining and prospecting activities," he said.

However, Mr Hickey's announcement was not without incident after sections of the audience criticised the Government's support of the opal mining industry.

Mr Hickey stressed measures had been taken to protect the local environment.

"To ensure future opal prospecting and mining in OPA 4 occurs in an efficient and responsible manner, only a limited number of opal prospecting blocks will be opened up for exploration at any one time,"

"Initially, this will be areas where there are no major environmental issues, or where significant mining activity has already occurred," he said.

Lightning Ridge Miners Association secretary Maxine O'Brien said it was a great relief and it has been a long time coming but the association would not be getting too far ahead of themselves.

"We have still got a few hurdles to get over yet especially to do with the new environmental conditions laid out by the minister," she said.

Ms O'Brien said the LRMA would meet with the minister today to gather a better understanding of how OPA 4 would be mined.

"It appears the plan is to mine areas where there has already been activity," she said.

OPA 4 covers an area of approximately 1600 square kilometres and is located 40 kilometres southwest of Lightning Ridge.

Mr Hickey said all prospecting and mining activities within OPA 4 would be subject to far stricter environmental conditions.