Employment lawyers have described the non-disclosure agreement (NDA) drawn up by Allen & Overy (A&O) for the settlement between disgraced movie producer Harvey Weinstein and his former assistant Zelda Perkins as being "perilously close to unenforceable" and containing "extraordinary" provisions.

The NDA in question – aspects of which were published online yesterday (28 March) by the Women and Equalities Committee investigating possible abuse of such agreements – was drafted by A&O employment partner Mark Mansell in 1998 after Perkins accused Weinstein of attempting to rape a colleague.

The agreement contains a number of details which have prompted surprise from employment law specialists, including provisions that prevented Perkins from being able to discuss details of the case with her doctor.

Michael Burd, chair and joint head of employment at Lewis Silkin told Legal Week: "It contains some things I have never seen before in 30 years of employment law. I've never seen details about what someone can tell their doctor. It's significantly more detailed and granular about things that must or must not be done than normal."

The NDA states if Perkins required medical treatment as a result of her allegations and her termination of employment, then she could not disclose details of her allegations with the doctor, who would also be required to sign a confidentiality agreement.

An employment lawyer at a US law firm said: "It's an extraordinary provision. We often see confidentiality agreements in settlements, but this is a different species."

Mansell yesterday (28 March) gave evidence to the Women and Equalities Committee – an 11-member group chaired by Maria Miller MP – and was asked whether he regretted the inclusion of a provision that required Perkins to limit her disclosures in cases of civil or criminal legal process.

Mansell stated: "If I was looking at dealing with that today, I would make it clearer that the ability to participate in a criminal process was not in any way restricted."

The NDA states Perkins had to give at least 48 hours notice to Mansell before making any disclosures in a civil legal process, and that she must "use all reasonable endeavours to limit the scope of the disclosure to legal advisers as far as possible".

DMH Stallard employment partner Jonathan Compton commented: "What the agreement does is provide a number of hurdles to prevent the giving of that evidence – for example, giving notice, limiting that evidence, and that Zelda must give 'reasonable assistance' to Miramax 'if it elects to contest such process'. The agreement comes perilously close to being unenforceable but probably (just) falls within what is lawful."

A letter drawn up by Mansell and sent to Perkins regarding her tax return was also released by the committee.

It states that when reporting the £125,000 paid to her as part of the settlement to HM Revenue & Customs (HMRC), she must direct any questions from the Inland Revenue about the payment to A&O.

Memery Crystal employment partner Stephen Ravenscroft said: "The provision on tax is unusual. Nowadays you would probably have to give a lot more information to HMRC to explain why a payment of that size could be received with any tax advantage. That would have to be handled in a different way."

Perkins, who also appeared before the committee yesterday, has called for reforms to NDAs, stating that she feels "let down" by the lack of law around them and describing her agreement as "morally lacking on every level". She also called for the introduction of a "disincentive" for lawyers to create such agreements.

An employment head at one UK top 30 firm told Legal Week: "There's a place for confidentiality, but what is not acceptable is significant issues being swept under the carpet through the use of an NDA. If significant allegations are made, then they need to be investigated properly. Using NDAs to cover things up or not looking into issues appropriately is not acceptable."

Burd added: "Such clauses should never be used to gag people or to prevent people from pursuing legal remedies they may otherwise have. There is no doubt that is what has been attempted in some NDAs in the past.

"Having said that, there is a role for confidentiality provisions in agreements which are resolving workplace harassment situations. In my experience there are not infrequently occasions where confidentiality is as important to the victim, because they do not want word getting out about what has happened.

"I have no doubt they may have been abused in the past, but that doesn't mean there is no place for them. I would hate to see a knee-jerk reaction that could harm or inhibit victims."