The provisions like termination with cause & without cause, the notice period upon such termination depends upon the Company's HR policies ofrthe employment contract and such provisions may differ form company to company. A company may have one month as its notice period and other may have two months or immediate. So if the terms and conditions of the employment contract are void or voidable within the meaning as mentioned under the Contract Law, then 'yes' it can be challenged by the party.
Also, the working hours, working conditions of the place of work may be covered by Labor Laws.