Total program spending under Harper increased from 12.5% of GDP in 2005/06 to 12.9% of GDP in 2014/15 (last full year Harper was PM) and 13.7% of GDP in 2015/16.

So Harper actually INCREASED budgets, not cut.

Looking at Direct Program Expenses, which excludes transfers to people (EI, OAS, etc.) and Transfers to other governments (health care), budgets decreased a hair from 5.9% of GDP to 5.8% of GDP in 2014/15, then back up to 6.2% of GDP in 2015/16.  That decrease however includes a 0.4% cut to military spending.

One can make a valid argument that Harper cut military spending too much, however all other department spending increased under the Conservatives.

Source: http://www.fin.gc.ca/frt-trf/2016/frt-trf-1602-eng.asp#tbl8