According to the statement by Minister Datuk Seri Dr Wee Ka Siong: “We are giving up to April 7 for them to enter Malaysia without any charge, but from April 8, they should have obtained their RFID tags or they would not be allowed to enter or may face action.”
Source: https://vep.jpj.gov.my/#/https://www.theedgemarkets.com/article/mot-receives-191293-vehicle-entry-permit-applications-singapore-vehicles-border-reopens/ 07 April 2022.