STATE COLLEGE, — Leaders of 18 state-supported colleges and universities are eyeing potential tuition hikes, layoffs and service cutbacks while rallying against Gov. Tom Corbett’s proposal to slash their funding more than 50 percent — considered the largest such proposed cut in higher education in the country.

In his first budget address Tuesday, Corbett called for $625 million in funding cuts for the 14 state-owned schools that make up the State System of Higher Education, and the “state-related” schools of Penn State, Pittsburgh, Lincoln and Temple. Those cuts represented the lion’s share of a 43 percent reduction in funding for higher education in Corbett’s budget for the fiscal year that starts in July.

School administrators said they had expected cuts, but not such deep ones.

“This is devastating news that could fundamentally change Penn State and our sister institutions in the state and have major negative impacts for the citizens of Pennsylvania and their families,” Penn State President Graham Spanier said at a news conference.

Corbett, a Republican, campaigned last year on a pledge not to raise taxes. He kept that promise in his $27.3 billion budget, which also would shrink overall state spending 3 percent and cut spending for public schools by $1 billion.

Spanier’s office said the higher-education cuts actually totaled closer to $660 million when taking into account cuts at medical schools at Penn State, Pitt and Temple.

The Washington-based American Association of State Colleges and Universities said Wednesday that Corbett’s proposal appears to be the biggest such cut in the country this year.

“This signifies a significant shift in policy, largely as a result of a new philosophic direction,” although Corbett has not explained the reasons behind his decision, said G. Terry Madonna, a pollster and professor at Franklin & Marshall College in Lancaster, which is not directly affected by the cuts.

The proposal cuts state appropriations for the state system and the four other universities by roughly half — about a $182 million cut for Penn State. For the state system, the cut would leave $232 million, which officials said was $2.5 million less than the system’s first appropriation in 1983-84.

The Association of Pennsylvania State College & University Faculties said the cuts could lead to a tuition increase of 33 percent and “decimate the state system.”

The union representing the 6,000 faculty members and coaches in the state system released a statement calling on people “to take action to prevent” the proposed cuts.