The chief executive of the Financial Markets Authority is leaving her role, with immediate effect.

Samantha Barrass intended to return to the United Kingdom to attend to family matters.

She had earlier been suspended from her role.

The FMA board had commissioned an independent employment investigation "concerning matters relating to" Barrass, with Paul Wicks, KC, to lead the investigation.

That was separate from a conduct and culture review.

Barrass had been seeking to overturn her suspension.

FMA chair James Miller said it had now ended.

There would be farewell events to "appropriately recognise" Barrass's contribution, he said.

Barrass said it had been a challenging five years.

"I have had great support from my executive leadership team and many others. We have lifted the performance of the organisation; I am really proud of them all," she said.

"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.

"I won't comment further on them at this stage. That's for the MBIE  (Ministry of Business, Innovation and Employment) investigation process to get to the bottom of, and I trust it will do so."