Former Abercrombie & Fitch CEO Mike Jeffries was recorded telling his British partner "we're screwed" and in "big trouble" if he was found fit to stand trial on sex trafficking charges later this year, a New York federal court has heard.

The audio was part of more than 100 phone calls between the ex-fashion boss and Matthew Smith referred to during a four-day mental competency hearing this week on Long Island.

Jeffries' lawyers argue that he is suffering with dementia and late onset of Alzheimer's disease and is unfit to face trial alongside his partner and their alleged middleman in October.

However, prosecutors say their medical experts found his condition has improved and that the calls reveal he is "incredibly focused" on being found incompetent.

In further recordings, Jeffries says he is "hoping for a good outcome", describing being found fit as a "disaster", and tells a doctor: "you better find me incompetent", Central Islip court heard.