An internal document quoted by the union shows staff will numbers will be cut from 1947 to 1596 - a decrease of 18 per cent.
The cuts would affect academic, general and technical staff, the union said.
An excerpt from the document accuses Government of pushing for the cuts as an "implicit'' condition of further investment in the university.
"The implicit message from the Tertiary Education Commission and the minister - that if the institution is willing to lead the way with cuts that could easily run to hundreds of jobs the State may invest in the university once more - is reprehensible,'' the passage states.
TEU national president Sandra Grey said the job cuts were being forced on the university.
It was expected to post a large deficit, partly due to costs associated with the Christchurch earthquake and the recovery effort.
She called for the institutions funding to be frozen at 2010 levels.
"Mr Joyce cannot sit by and let one of New Zealand's most prestigious learning institutions bleed nearly a fifth of its staff.
"In terms of Canterbury as a region and New Zealand as a whole... this kind of cut to staff has major implications.''
A spokeswoman for Tertiary Education minister Steven Joyce said he would respond to later today.
