Gray, whose appointment was broadly welcomed by the industry, was named as the replacement for veteran Martin Ferguson who resigned on Friday after backing a failed coup against Prime Minister Julia Gillard.
Resources is a critical portfolio in Australia as the country rides a mining boom, with the bitterly fought mining tax designed to spread the benefits of the boom around the nation contributing to the downfall of ex-PM Kevin Rudd.
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Rudd attempted to introduce a 40 percent tax on mining "super profits" in May 2010, provoking a backlash from the powerful industry. Within months he had been replaced as Labor leader by his deputy Julia Gillard.
Gray, who was a senior executive with Woodside when he left the company in 2007, said there would be no conflict of interest given the people he used to work with during his six years at the firm had since moved on.
"The management team with whom I had great personal familiarity have gone," he told Fairfax Radio.
"I certainly don't have any Woodside shares."
Nicole Roocke, director of Western Australia's Chamber of Minerals and Energy, agreed Gray would not be compromised by his former job.
"We don't see that it will put him in a difficult situation," she said.
The Greens have objected to the appointment of 54-year-old Gray, saying he would not look good given he had come "straight out of an executive position of Woodside".
But the Australian Mines and Metals Association (AMMA) welcomed the move, saying Gray, who also became minister for tourism and small business, was highly regarded by the sector.
"As a Western Australian and a former executive with Woodside Petroleum, Minister Gray should bring a strong understanding of the booming offshore oil and gas industry to the role, including the need for the sector to remain competitive and sustainable in the long-term," said AMMA chief Steve Knott.
