The Department may establish such reasonable regulations as the Department may deem appropriate with respect to the qualifications of contractors allowed to bid on work of the Department. Such regulations may fix eligibility requirements for bidders according to available capital and with due regard to experience and records of past performance. But in no case shall the eligibility rating of any bidder be influenced by nationality or place of residence. No regulations with respect to the qualifications of bidders shall become effective until at least thirty days after such regulations shall have been formally adopted and published.