Under current legislation, your employer is required to pay an amount equal to 9% of your ordinary time earnings into your super account until age 70. This requirement is know as the Superannuation Guarantee (SG). Employers who do not make these payments have to pay an "extra amount" known as the Superannuation Guarantee Charge (SGC) to the Australian Taxation Office, as well as pay you what is owed.
Caps apply to contributions made to your super account. Any super contribution over the cap amount is subject to extra tax.
Employer contributions are counted against the concessional contribution cap.
Check out the Better super booklet for more information.