Student hackers have forced the Victorian Tertiary Admissions Centre website to lift its information embargo on first round offers.

The site was supposed to open for students at 2pm on Monday, but hundreds who could not wait began hacking in to get their results from Sunday using instructions posted on Facebook and chat forums.

VTAC has said it would review its traditional "lockdown" after the breach was discovered.

A group called VCE Discussion Space posted instructions on getting into the offers site on its Facebook page. These then spread to another forum, ATAR Notes, a group about the Australian Tertiary Admissions Rank, the system used to compare students who have completed different combinations of Year 12 courses.

"Hey guys, the following is from VCEDiscussionSpace on FB - you can check your first round offers now. I guarantee it works, just follow the steps below," the ATAR Notes site said.