The Cook Islands opposition MP Selina Napa has asked the government to reveal what changes are being planned for the Seabed Mining Act.
Ms Napa said reported statements that the changes would be made public when they are tabled in Parliament "isn't good enough".
Requests to the Seabed Minerals Authority to see what the law changes are have been met with refusal as the draft is currently with the Crown Law Office, she said.
"We wanted to know what they are up to before it even reached Crown Law," she said, adding that "the lack of transparency does nothing to instil confidence that the law changes the government is planning are in the best interests of the Cook Islands people, the country and environment."
The Titikaveka MP said an expert team from the Commonwealth Secretariat was engaged by the then Democratic government in 2007 to draft the act and the Cook Islands did not have the expertise to change it without posing a threat to the environment.
"It really worries me that they are tinkering around with this ground breaking, hugely important legislation that was drafted by experts in law of the sea and the blue economy.
"I don't think we have the expertise to be making any kind of changes that will affect the Seabed Mining Act in any way."
It is also very concerning that mining companies with an interest in obtaining exploratory licenses in the Cook Islands exclusive economic zone could be helping the government develop a plan towards achieving this activity, Ms Napa said.
"We've already stuffed up the purse seining agreement with the European Union. We came away with nothing in our favour, those negotiations had just the former secretary of Marine Resources and one lawyer from Crown Law going toe to toe with a team of the biggest guns from the EU. So we ended up second best, got locked into an unfavourable agreement and today we are selling our fish for a pittance," she said.
"Personally, I prefer to leave whatever is on our seabed undisturbed, let it be. But since the government is hell bent on pursuing the exploitation of our seabed minerals, everyone in their right mind wants this to be done with the outmost caution and ensure that the best, most robust team does all of the negotiating on our behalf. This responsibility can't be left to just our heads of agencies and lawyers with little or no relevant experience.
"The current team which seems to be meeting with interested mining companies really don't have the required expertise to negotiate the best deal and protect the interests of our country."
The government plans to open tenders for five-year, deep sea mining exploration licences at the beginning of next year.