If upon the effective date of this act a covered employer has in effect a plan for the payment of cash disability benefits to his employees or to any class or classes thereof, or has in effect an agreement with a union or association whereby there is in effect a plan for the payment of cash disability benefits to his employees or to any class or classes thereof (and to the cost of which plan the employer is obligated to contribute,) such plan shall, regardless of the requirements of this article, be deemed to be an approved private plan until the earliest date upon which the employer shall have the right to modify the benefits of or discontinue such plan, or to discontinue contributions toward the cost thereof. In such case the employer shall notify the commission of the circumstances. During the continuance of such private plan the employees covered thereunder shall not be entitled to any benefits under the State plan with respect to any period of disability commencing while they are covered under such private plan. If any such private plan covers only a class or classes of covered individuals, the employer may effect another private plan for his remaining employees or for a class or classes of them, subject to the requirements and limitations of section eight.
N.J.S. § 43:21-34