Sprent Dabwido struck a deal with Julia Gillard in 2012 for his impoverished Pacific island to once more be used for offshore processing of asylum seekers and refugees.

Mr Dabwido now regrets signing the agreement, which was worth hundreds of millions of dollars.

"I think I've caused a bit more problem than I ever thought I would," he told The Project on Network Ten.

"There's nothing much I can do but just say I'm very sorry that I thought I was doing the right thing at that time."

Mr Dabwido, who is now terminally ill, described the agreement as a "deal with the devil".

He implored the government of Nauru to rip up the deal and force Australia to find somewhere else for the hundreds of people detained on the island.

"Nauru government should find a better way than living on these people's blood," Mr Dabwido said.

"Lives have been lost. Corruption and greed has overtaken my island."

Mr Dabwido said he was being "very naive" when he signed the original contract.

"I thought we could quickly establish ourselves and put the money aside and get the country back on its feet," he said.

"But what it did was, it did the opposite."

Australian Associated Press