Animal rights activists filed a civil suit against the government last week, preventing the export of the animals to Resorts World Sentosa.
They alleged the capture of the bottlenose dolphins from the Solomon Islands, as well as their transport to Singapore after being trained, violated an international treaty on the trade of endangered animals and plants.
The case was later transferred to another court, which lifted the travel ban on Wednesday.
Theresa Concepcion, Asia head of the animal rights group Earth Island Institute, said it planned to appeal the latest ruling on Friday.
“This is a sad day for dolphins. The lifting of the (court injunction) means we can now trade in any species even if this would affect the survival of these species in the wild,” she told Agence France-Presse.
The dolphins had been captured in the waters of the Solomons, according to Concepcion, and were shipped away to be trained at a marine entertainment park in the Philippines between December 2008 and January 2011.
Bureau of Fisheries and Aquatic Resources chief Asis Perez said the government agency granted an export permit for the dolphins last week, but the first court action temporarily suspended it.
“The restraining order has been lifted, so they are free to export them,” Perez told AFP.
The latest ruling by Regional Trial Court Judge Evangeline Marigomen said: “The… petitioners have not proved any violation of law committed by the concerned government agencies.”
Perez said the owners had not told the Philippine government when it planned to transfer the animals to Singapore.
The company’s Manila lawyer was unavailable for comment on Thursday.
Resorts World Sentosa put out a statement in Singapore on Wednesday saying it looked forward to the dolphins’ arrival.
“Our dolphins are doing well under the care of our team of experienced experts, and we look forward to welcoming them to Singapore,” it said.
It disputed the animal rights groups’ allegations, insisting it had contravened no international treaties in acquiring the dolphins.
Swiss-based conservation group International Union for the Conservation of Nature said on its website that bottlenose dolphins were “widespread and abundant”.
However Earth Island argued in court that the Solomon Islands’ ban on dolphin hunting in its waters imposed this year showed that the local population was under threat.