Yesterday she said she made a mistake and should have included it from the beginning.
Prime Minister Jacinda Ardern stood by Curran, saying she had corrected the record - though it had taken two and a half months and she should have done it sooner.
Curran and Hirschfeld communicated by text for several days ahead of their meeting, Stuff reports. It said Curran's office had confirmed the meeting was arranged by text. It says a process is "in train" to release the messages.
Curran remains in the spotlight for what was said in the meeting and whether it could be seen as an attempt to influence the editorial direction of the state broadcaster, which is set to receive $38 million in Government funding to set up RNZ Plus.
Curran called it a "high-level discussion" about the state of the media and Radio NZ's future, but a spokeswoman late last night insisted that "the minister was not trying to push RNZ in any direction".
Ardern also said that Curran had assured her that there was nothing inappropriate in her discussion with Hirschfeld.
Curran also defended her decision not to set the record straight publicly after she found out on March 1 - following a select committee meeting with Radio NZ bosses - that Hirschfeld was calling it a chance encounter.
She said her office contacted Radio NZ immediately to correct Hirschfeld.
"It then became a matter for RNZ to deal with."
RNZ bosses questioned Hirschfeld about the matter again, who reassured them it was a chance meeting.
Curran said her office again contacted Radio NZ earlier this week to say it was a pre-arranged meeting. On Sunday, Hirschfeld admitted the meeting was pre-planned, leading to her resignation yesterday.
Curran said she may have been naive to hold the meeting, and would not have held it if she had known about Radio NZ protocols about meetings.
Asked why Hirschfeld persisted in describing it as a chance meeting, Curran said: "You'd have to ask her."
Yesterday Hirschfeld went to ground, but in a statement, Radio NZ chair Richard Griffin and chief executive Paul Thompson said they were "very disappointed".
Based on what Hirschfeld had told them, Griffin and Thompson inadvertently misled a parliamentary select committee on March 1, telling MPs that Hirschfeld had been at the gym when she chanced upon Curran.
Curran was first asked about her meetings with Radio NZ staff on December 7. She did not list her meeting with Hirschfeld, and corrected her answer after being grilled about the meeting during Question Time on February 20.
Opposition leader Simon Bridges said Curran was in "real trouble" for misleading Parliament in her original answer, but he stopped short of saying she should resign.
"This was in her diary. She left that out [of her written answer]. We're then left with the impression of something informal, something coincidental. That was patently false.
"Is that good enough? Frankly, I think it's misleading."
Ardern said she had full confidence in Curran. "She corrected the record. It just shouldn't have taken so long."
The Economic Development, Science and Innovation committee also released its 2016/17 annual review of Radio NZ yesterday.
"RNZ told us that the Minister of Broadcasting ... does not have an influence on the content it produces," the report states.
"The protocols around meeting with ministers and political transparency have been clearly outlined to senior members of staff since the incident."
Timeline:
• Dec 5: Broadcasting Minister Clare Curran meets with RNZ head of news Carol Hirschfeld at Astoria Cafe in Wellington and discusses, among other things, the future of RNZ.
• Dec 5: Media commentator John Drinnan blogs about the meeting, saying any discussions about the future of RNZ should be with board chairman Richard Griffin or chief executive Paul Thompson.
• Dec 7: National MP and broadcasting spokeswoman Melissa Lee asks Curran for a list of meetings with RNZ staff since Dec 1. Curran initially answers that she met Thompson, Hirschfeld and other senior RNZ staff on Dec 7.
• Feb 20: Lee uses Question Time to ask Curran about meeting with Hirschfeld. Curran eventually says she did not list the meeting in her written answer because she did not consider it to be an official meeting.
• Feb 21: Curran corrects her answer to Lee's Dec 7 question, adding her Dec 5 meeting with Hirschfeld.
• March 1: At a select committee Lee questions Thompson and Griffin about the meeting and is told it was a chance encounter.
• March 1: Curran hears about the select committee hearing and her office tells RNZ that the meeting was pre-planned. Thompson asks Hirschfeld about the meeting again, and Hirschfeld reassures him it was a chance encounter.
• March 22: Curran's office contacts RNZ again to tell them the meeting was pre-planned.
• March 25: Following a tip-off to Griffin, Hirschfeld is asked again and admits the meeting was pre-arranged.
• March 27: Hirschfeld resigns. Curran says it was a mistake to say the meeting was informal and unofficial. Jacinda Ardern says Curran should have corrected her answer to the written question sooner, but has full confidence in the minister.