Plans to pump oil between tankers in the Firth of Forth could be blocked by Scottish ministers under new powers to be considered at Holyrood this week.
Ship-to-ship oil transfer plans have angered environmentalists
Currently, harbour authority Forth Ports has the final say on proposals to pump millions of tonnes of Russian crude oil between ships.
The legal change would allow ministers to veto developments which threaten protected wildlife areas.
The move has been welcomed by the Green Party and environmental groups.
Under a specially accelerated procedure, a statutory instrument giving ministers extra powers under the European Habitats Directive will be put before the Scottish Parliament.
It is expected to be passed before the summer break.
The draft instrument, which was lodged in the parliament late on Friday, provides "new powers for Scottish ministers to call in a plan or project which they consider may have a significant effect on a protected site".
Ministers will also be able to suspend projects if certain conditions have not been met.
The proposals from SPT Marine Services would see about 7.8 million tonnes of Russian crude oil a year pumped between tankers anchored four miles off the coast.
The plan has been met with fierce opposition from local councils, communities and environmental groups.
Last month, Environment Secretary Richard Lochhead asked Forth Ports to freeze plans for the transfers.
He also expressed concern that the harbour authority was both "judge and jury" of the project.
First Minister Alex Salmond has previously called for tighter government controls over the plans.
The Scottish Green Party said the new powers were based on the proposals originally made by them.
The issue was agreed as a priority for action during talks between the Greens and the Scottish National Party immediately after the Holyrood election.
Green co-leader Robin Harper said: "Shifting power back to ministers using Habitats Directive regulations is the right way to bring about swift action on this threat.
"It is an absolute priority that the public interest be upheld, and that key decisions of such immense importance are made by the right people and for the right reasons.
"The Forth marine environment is of world heritage significance, is vital to the local economy and developments must be subject to proper scrutiny."
A spokeswoman for the executive said: "Ministers are looking forward to making an announcement on this issue next week."