On Wednesday the court ruled the Australian Government has a constitutional right to declare another nation a regional processing country, including PNG.
An Iranian man brought the High Court case after he was taken from Christmas Island to Manus Island last year.
O’Neill says he is confident a similar legal challenge currently before the Supreme Court of PNG will find offshore processing to be within the laws.
“When we agreed with the government of Australia to implement this policy, we were confident about what this would achieve,” O’ Neill said in a statement on Sunday.
“For six months now there has been no report of any illegal boat arrivals in Australia.
“Assessment of asylum claims is now progressing well with the majority indicating a return to their home country.
“Development projects agreed to under the deal with the Australian government, like the construction of a new Angau Hospital in Lae, are being implemented.”
O’Neill says the people of Manus Island are “now benefiting” from the agreement with Australia.
“People smuggling is one of a number of regional and global challenge that PNG can help address, and we remain committed to working with Australia or any other country address this issue,” he added.
O’Neill said he will also meet with Acting Police Commissioner Geoffrey Vaki this week to discuss the police investigations into the riot at the detention centre in February that left Iranian Reza Barati dead and more than 60 other asylum seekers injured.
Australia’s Prime Minister Tony Abbott has also welcomed the decision.
“This is a government that is determined to stop the boats,” he said.
“We haven’t had a successful people smuggling venture to Australia in almost six months and obviously I’m pleased those policies have passed muster.”