Greenpeace wrote a scathing letter to the ship's owners, saying: "many unanswered questions remain. Why was your vessel sailing so dangerously close to the reef? Why have you done so little since the ship ran aground? What will you do to reduce the damage to the environment, and the pain and suffering of those whose livelihoods depend on it?"
The ship's owner has meanwhile pledged to "sincerely" respond to requests for compensation over damage to the marine environment.
"We are deeply conscious of our responsibility as a party directly involved in the case," said Kiyoaki Nagashiki, president of Nagashiki Shipping.
"Regarding compensation, we plan to deal with the issue sincerely based on applicable laws," the head of the Okayama-based company said in a statement.
"We will continue to do our utmost to collect the leaked oil and to minimise the impact of the environmental pollution," he added.
In an interview with AFP on Thursday Prime Minister Pravind Jugnauth said a probe into events surrounding the disaster was still ongoing.
"The investigation will be able to determine the causes of this accident, the reasons why the boat came so close to our shores and ran aground," Jugnauth said.
"And of course, a general mobilisation at all levels will continue cleaning up and making sure that the oil can be removed from the sea."