The migrants have been living in makeshift camps in the forests of central Sweden, amid simmering tensions with local residents, after being lured there by suspected human-traffickers with promises of seasonal work.
Since last week, hundreds of them have also camped outside the Bulgarian embassy in the capital Stockholm, seeking help to get home.
Bulgarian ambassador Svetlan Stoev told the TT news agency:
"We are working to get them all home to Bulgaria. But we need help finding buses."
Mohlin said the about 200 people who were camping outside the embassy would leave by Thursday morning, as soon as enough buses had been located.
On Monday, a 43-year-old man, whose name was not given, was detained in Sweden suspected of human trafficking, after a number of Bulgarians reported to local police he had tricked them into making the trip.
Local police in the central Uppsala region said the man had recruited the Bulgarians and promised them housing, food and decent salaries.
But after he drove them up in a bus, the migrants told police, they were handed tents and basically left to fend for themselves in what has been shaping up to be a disastrous berry season due to poor weather.
Locals in nearby villages and towns have for weeks voiced concern about the squalid conditions of the large camps, without easy access to food or sanitary facilities, and the strain it was putting on local communities.
Many have made their way down toward Stockholm and the embassy, and to accomodate their needs the city made a school building in central Stockholm available on Wednesday night. Resources however remained stretched.
"I am trying to call round to the different local authorities in the municipalities that have many stranded pickers and ask them to keep them up there. Otherwise we risk a situation we can't manage down here," said Mohlin to TT.
Mohlin was very pleased with the news from Bulgaria, but added that getting the stranded pickers home will be no easy feat.
"It is hard to find buses and drivers, the embassy is working hard to solve the situation. And then the pickers need to be identified, to ascertain that they really are Bulgarian," Mohlin told TT.