The rescue attempt, proposed by two entrepreneurs, will involve lifting the whale using inflatable cushions and transporting it with pontoons, said Till Backhaus, environment minister for the state of Mecklenburg-Western Pomerania.

"We have decided that a rescue of the whale, while it is still alive, can go ahead. We are thus opening up the possibility, for the first time, of returning the animal to its natural habitat," Backhaus said.

Local authorities had two weeks ago declared it was no longer possible to save the whale after it became stranded near the island of Poel, close to Wismar.

The 13.5-metre (44-foot) animal had by then been floundering off Germany's Baltic Sea coast for more than a week, having first been spotted stuck on a sandbank on March 23 near the city of Luebeck.

The whale became stuck and then freed itself again several times, with experts initially hoping it would be able to find its way back to the Atlantic Ocean.

But on April 1, regional officials said they were convinced that the badly injured and distressed animal was going to die and could no longer be saved.

Coverage of the whale's struggle for survival and efforts to rescue it have gripped the German public, with some of the press calling him "Timmy".

Regular demonstrations have been held in support of the stricken creature, with protesters calling for rescue efforts to resume and some online posts targeting officials with death threats.

Previous rescue proposals, including the use of a catamaran, were ruled out because it was concluded the whale would probably not survive them.

One of the entrepreneurs behind the new plan is Walter Gunz, founder of the MediaMarkt electronics retail chain.

Backhaus said there was now a "chance" for the whale but it remained "in a difficult condition" and "seriously ill".

"The prognosis is and remains critical -- that is perfectly clear. But there is now a plan," he said.