K filed an action directly in court against the government seeking payment for a parcel of land which the national government utilized for a road widening project. Can the government invoke the doctrine of non- suitability of the state?

NO. When the government expropriates property for public use without paying just compensation, it cannot invoke its immunity from suit. Otherwise, the right guaranteed in Sec. 9, Art. III of the 1987 Constitution that private property shall not be taken for public use without just compensation will be rendered nugatory. (Ministerio v. CFI, G.R. No. L-31635, August 31, 1971)