The Government has announced from the 24th of May 2018, a 1 year Superannuation Guarantee Amnesty. This is a rare opportunity for employers to pay their overdue super liabilities without paying the ATO penalty and receiving a tax deduction for the payment. If employers with outstanding payments do not comply in the 1 year period, there will be harsher penalties. Please see the below link for more information.
https://www.ato.gov.au/Business/Super-for-employers/Superannuation-Guarantee-Amnesty/