"My position is that New Zealand defends the freedom of press, no matter where in the world that freedom is being exercised, or is attempted to be exercised," she said.
Fiji's Prime Minister Frank Bainimarama said this morning that his Government "immediately demanded" the trio's release upon learning of their detention.
The media was an ally in accountability over Freesoul, which Bainimarama said was a company demanding the highest level of public scrutiny.
"I have spoken with the Commissioner of Police who has assured me the detention of these journalists was an isolated incident undertaken by a small group of rogue officers.
"A full investigation into why these officers would use such heavy-handed tactics will be undertaken, and any violations of protocol or undue influence will be met with appropriate action," the Fiji PM said.
"I – together with my Minister for Environment and the Commissioner of Police – will meet with the journalists later today to apologise for the treatment they've received and personally speak with them about our position on the environment, particularly with regards to development," he said.
Speaking to media this afternoon, Foreign Minister Winston Peters said the Kiwi journalists were "going about their lawful media job".
Peters said they were "in some way detained – not in the way you would think in a prison cell."
"They were taken to restaurant; they were given a meal and the whole 100 yards – which is not what sounds like normal detention."
Peters said he was trying to get to the bottom of what happened: "But what I do know is the circumstances of them being asked to make themselves available for questions by those police, who are now themselves being questioned, are very different from what you would normally expect.
"You don't expect to be taken to a restaurant during events."
Newsroom co-founder Tim Murphy said Peters was trying to dimish the detention and that the journalists "were escorted by cops at midnight to McDonalds."
Peters noted that Bainimarama had confirmed the trio were no longer being detained.
"They will be subject to an apology from him and the matter will be sorted out as best we can in the circumstances."
Peters said Bainimarama had been "most effusive" about his apology.
"He seems to be enormously supportive of the rights of these three journalists to find out what was going on."
"They have been removed from where they are, they are going to be the subject of a personal apology from the Prime Minister of Fiji, Bainimarama, so how much further can we go?"
Peters would not be drawn on the issues the journalists were said to be investigating.
But he did say: "On the face of it, it seems to me that three journalists were interested in the offence to the environment, so to speak, making an investigation of it, some police got totally out of hand – probably on a local level – and they have been put to right and the Prime Minister is going to apologise."
Peters said any accusations that Fijian police were acting in a rogue way would be investigated.
"In the meantime, I can say the New Zealand High Commission was involved in talks with the authorities about the detention."
But Peters said he was not directly involved in the matter: "I only learned about it this morning and was trying to find out what our High Commission was doing".
Newsroom reported this morning that its co-editor Mark Jennings, investigations editor Melanie Reid and cameraman Hayden Aull were earlier in a holding room at Totogo police station having been accused of criminal trespass by the developer Freesoul Real Estate.
Newsroom reports that it is understood the real estate company claims the investigative journalists walked past a sign which read "authorised staff only".
It further reported that they had not been charged but were likely to undergo police interviews this morning.
Reid, whose career includes 25 years at TV3, said the arrest was "ridiculous".
"We walked into the Freesoul office in Suva with a camera and asked why they had been operating at Malolo with no permits," she told Newsroom.
"We asked to talk to Freesoul director Dickson Peng. We were told to leave and we did.
"This is trumped up and ridiculous.
"I've worked all over the world and never been taken into custody for asking questions in a public office - questions, I might add, that desperately needed to be asked."
Reid was named reporter of the year at last year's Voyager Media Awards.
National's Foreign Affairs spokesperson Todd McClay had called the detention of the three Newsroom journalists unacceptable.
"Freedom of the media is a fundamental principle of democracy and journalists must be free to tell important stories and ask important questions," McClay said.
"New Zealand has committed more than $60 million of development assistance and aid to Fiji over the next three years."
New Zealand expects Fiji to respect the fundamental freedoms of democracy, he said.
"Mark Jennings, Melanie Reid and cameraman Hayden Aull should not have been arrested.
"Through their actions Fiji is putting at risk its improving relationship with New Zealand.
"The Government must warn Fiji that these actions are not acceptable and demand that journalists must be free to do their job."
It is not the first time a New Zealand reporter has been detained while working in Fiji.
A high-profile example was when TVNZ Pacific correspondent Barbara Dreaver was detained in Fiji in 2008 and subsequently banned from the country.
In 2016, the Fijian government announced journalists were again free to visit the country and report without restriction albeit as long as they were accredited by the Department of Information.
Dreaver returned to Fiji later that year after an invitation was made by Bainimarama.
