The suspended CEO of New Zealand’s Financial Markets Authority is leaving the role early.

Samantha Barrass, who was fighting the suspension, had told the FMA she would not seek a renewal of her term when it expires in January.

She is now returning to the UK for family reasons, so the board has agreed she will leave the authority. Board member Alastair Hercus will be acting CEO.

Last month, the FMA board announced it had commissioned an employment investigation concerning matters relating to Ms Barrass.

The Ministry of Business, Innovation and Employment separately said it was investigating “conduct and culture” at the authority.

FMA chair James Miller says the board’s investigation will be subsumed by the MBIE investigation.

In a statement, Ms Barrass said it had been a challenging and rewarding mission reforming and expanding the regulator.

“The last few weeks have been very challenging for me, as I have found myself on the receiving end of allegations, and where I have had to take time out for them to be investigated,” she said.

“I won't comment further on them at this stage. That’s for the MBIE investigation process to get to the bottom of, and I trust it will do so.”

Ms Barrass joined the regulator five years ago after working for the UK financial regulator and establishing the Business Banking Resolution Service there.

She began her career at the Reserve Bank of New Zealand.