Yes, you can submit a new application for the same qualification you withdrew from previously. In MyWaikato go to 'Qualifications and Papers' and select 'Start a new application'.
If you want to reapply for the same intake (semester and year) you withdrew from, you may see a message in MyWaikato preventing you from progressing. If this happens, contact us by logging an enquiry, emailing info@waikato.ac.nz or by calling 0800 WAIKATO (0800 924 528) or +64 7 838 4610 from overseas.