a. No homestead rebate or credit shall be allowed pursuant to this act except upon annual application therefor, in any manner, upon any form, and in any format, whether in writing or otherwise, as shall be prescribed by the director. The director may require a claimant for a homestead rebate or credit to attach to the homestead rebate or credit application a copy of the appropriate property tax bill or proof of rent paid for the prior tax year. The director may require such other verification of eligibility for a homestead rebate or credit as the director may deem necessary. The director may require that the application for a homestead rebate for a unit of residential rental property authorized pursuant to section 4 of P.L. 1990, c.61 (C.54:4-8.60) shall be submitted (1) as part of the claimant's gross income tax return filed pursuant to the "New Jersey Gross Income Tax Act,"N.J.S. 54A:1-1 et seq., or, (2) on any other form, in any manner or format and at any time and prior to any date as the director shall prescribe if (a) the claimant is not required to file a gross income tax return or (b) the claimant has filed an application for extension of time to file the claimant's gross income tax return. The director may require that the application for a homestead rebate or credit authorized pursuant to section 3 of P.L. 1990, c.61 (C.54:4-8.59) shall be submitted (1) as part of the applicant's gross income tax return filed pursuant to the "New Jersey Gross Income Tax Act,"N.J.S. 54A:1-1 et seq., or (2) on any other form, in any other format and at any time and prior to any date as the director shall prescribe. The director shall, for good cause shown, extend the time of any applicant to file a claim for a homestead rebate or credit for a reasonable period, and in such case, the application shall be processed and payment of a homestead rebate or credit made in accordance with the procedures established in the case of applications timely filed, except the date for payment of the rebate or credit may be delayed for a reasonable period. If an applicant or an applicant's spouse has filed an application for an extension of time to file a gross income tax return, the date by which the applicant shall file the homestead rebate or credit application may, in the discretion of the director, be extended for a reasonable period, and the date for the payment of the rebate or credit may be delayed for a reasonable period. The director may require sworn applications. In the event that the director waives the requirement of sworn applications, all declarations by claimants shall be considered as if made under oath and claimants, as to false declarations, shall be subject to the penalties as provided by law for perjury. For the purposes of this subsection, in order to establish good cause to extend the time of any applicant to file a claim for a homestead rebate or credit the applicant shall provide to the director either medical evidence, such as a doctor's certification, that the claimant was unable to file the claim by the date prescribed by the director because of illness or hospitalization, or evidence that the applicant attempted to file a timely application. Except as may be established by medical evidence of inability to file a claim, good cause shall not be established due to a claimant not having received an application from the director.