Twenty-one-year-old Somali refugee Hodan Yasin was been transferred to Australia in a critical condition after setting herself on fire on Monday.
It follows the death of 23-year-old Iranian asylum seeker Omid Masoumali, who also self-immolated on the island, ABC News reported.
Speaking in Canberra yesterday, Dutton accused advocates of providing false hope to those have been held in offshore detention.
"I have previously expressed my frustration and anger at advocates and others who are in contact with those in regional processing centres and who are encouraging some of these people to behave in a certain way, believing that that pressure exerted on the Australian Government will see a change in our policy in relation to our border protection measures," Dutton said.
"They can oppose Government policy and espouse a cause for open borders, but that is not the policy of this Government, and no action advocates or those in regional processing countries will cause the Government to deviate from its course."
But Pamela Curr from the Asylum Seekers Resource Centre said advocates such as herself were trying to keep the detainees calm and give them something to hold on to.
"I know that there are advocates out there, like me, who are texting, messaging, WhatsApping all the time," she said, reported by ABC News.
Curr said advocates were telling detainees to "try and stay calm, keep feeling hopeful, don't go into the ocean", and said women wanting to drown themselves was another concern.
"Of course we don't want them to hurt themselves," she said.
Curr said she knew Yasin and said the woman was "beside herself with distress" after being returned to Nauru from Australia.
Dutton said Yasin was receiving the "utmost care" after being flown from Nauru to a Brisbane hospital.
"It is of grave concern that this person would resort to such an extreme act of self-harm," he said.
And he accused asylum seeker advocates of contributing to the increased tensions in Nauru.
"The behaviours have intensified in recent times and as we see, they have now turned to extreme acts with terrible consequences," he said.