Peter Beggs was dismissed from his role as chief executive at Antarctica NZ.

Antarctica New Zealand chief executive Peter Beggs was sacked after an investigation, its board's chair has disclosed.

In a written statement to Stuff on Monday night, board chair Sir Brian Roche said Beggs was dismissed and would be paid only his contractual entitlements.

The announcement came after mounting pressure on the board to provide more details about Beggs' sudden departure from his important role last week.

MONIQUE FORD/STUFF Antarctica NZ chairman Brian Roche said Peter Beggs was dismssed from his role as chief executive.

Prime Minister Jacinda Ardern was asked about the turmoil at Antarctica New Zealand at her post-cabinet press conference on Monday and said it was an operational matter on which she had no more information.

Beggs told a reporter his family hoped to return to the United Kingdom where his children's grandparents lived.

Peter Smith has been named acting chief executive at Antarctica NZ.

SUPPLIED Sharon Hunter said she quit the board a few weeks ago to support her 18-year-old daughter.

Roche would not elaborate on his statement but sources told Stuff the investigation took between four to six weeks and discovered misconduct and failures of judgement.

No other authorities had been called in but the lapses showed conduct below what was expected of a chief executive in the public sector.

The sources said Beggs had not been given the option of resigning.

"He was fired," one said. "Resigning was never on the cards apparently."

Antarctica New Zealand staff were told about the dismissal last night. Earlier they had simply been told Beggs was leaving.

Beggs wasn't the only sudden departure from Antarctica New Zealand in recent weeks.

Antarctica NZ board member Sharon Hunter, an IT entrepreneur, also left the agency unexpectedly, saying she had to spend more time with her unwell daughter.

Hunter and her husband Tenby Powell are currently in Los Angeles.

The agency, which received $20 million in public funding last year, oversees the running of Scott Base in Antarctica and scientific research programmes on the ice.

​It is currently preparing a business case for an estimated $150m replacement for the ageing Scott Base.

Beggs, who took up the post in 2014, represents New Zealand on a number of international bodies.

He is being approached for further comment.

Hunter was appointed to the seven-member board in late 2015 for a three-year term.

Also on the board are former Kiwibank chairman Rob Morrison, TVNZ chairwoman Dame Therese Walsh, former Air NZ chief executive Rob Fyfe and former Sky TV lobbyist Tony O'Brien.