The phrase "national level" refers to something that is related to a whole country. It is used to describe actions, decisions, or events that are happening on a large scale, affecting the entire nation as a whole. Full definition
I have present many papers at national level conferences on the relation between effective internal financial management and profits. (resumetemplate.org)
It aligns positive action with economic gain and encourages enforcement by peers within the region, rather than relying on national level policies that are difficult and expensive to monitor and enforce. (dotearth.blogs.nytimes.com)
Growing up he competed at both the provincial and national level in tennis. (lklaw.ca)