The federal government has given conditional approval to two major coal seam gas projects in central Queensland.
Environment Minister Tony Burke told a media conference in Canberra on Friday his department had given conditional environmental approvals for Gladstone Liquefied Natural Gas (GLNG) - a joint venture between Santos, Malaysia's Petronas and France's Total - and BG Group's Queensland Curtis LNG.
Burke said he has imposed 300 conditions on each project, aimed at protecting the areas affected, the ABC reported.
"While there are significant economic benefits which must be a consideration in my decision, my focus has been on protecting environmental matters," he said.
"I've also considered potential impacts on agricultural land.
"Among other economic and social matters, we must protect the Great Artesian Basin, our threatened species, our waterways and the Great Barrier Reef", the ABC reported the Minister as saying.
They aim to produce a combined 15.7 million tonnes a year of LNG, equivalent to nearly 90 per cent of current Australian LNG exports.
Queensland Treasurer Andrew Fraser earlier said the parties had been working hard to ensure the projects proceed according to the strictest of environmental standards, but also spruiked the financial plusses.
"This is Queensland's opportunity to create a whole new multibillion-dollar export market, and potentially 18,000 Queensland jobs," he said in a statement.
Yet Mr Burke's long-awaited decision comes in the wake of calls for a moratorium on the coal seam gas industry after a spate of contaminations at Queensland operations.
On Tuesday, toxic chemicals were found in eight exploration wells at a central Queensland coal seam gas operation.
Four toxic chemicals - benzene, toluene, ethylbenzene and xylene - were discovered in the hydraulic fractured wells in the Surat Basin, near Miles, Origin and its Australia Pacific LNG joint-venture partner ConocoPhillips revealed.
In mid-July, the Queensland government suspended Cougar Energy's underground coal gasification project near Kingaroy, in the state's southeast, after underground water was contaminated with benzene and toluene.
Friends of the Earth spokesman Drew Hutton urged the minister to take a cautious approach.
"The companies should not be given approvals to go ahead with any development of the gas fields until they can provide environmental management plans that contain proper modelling of underground water systems and measures taken to minimise risk to these," Mr Hutton said in a statement.
"Given the irresponsible gold rush attitude of the Bligh government and the LNP (Liberal National Party) opposition to these projects, Mr Burke has a heavy responsibility to bring some clear thinking to the approvals process."
Capricorn Conservation Council spokesman Michael McCabe said the projects could threaten dugongs, dolphins, turtles, fisheries and other marine life.