Where any municipality has issued bonds for special improvements, and special assessments have been levied to pay for said bonds, or wherein the municipality was to have paid a portion or all of said bonds under any special improvement law by which said bonds were issued, and said installments for special improvements have not been collected, or funds for the payment of said bonds are not on hand, such municipality is hereby authorized to issue refunding bonds in the manner provided by general law for the refunding of bonds by municipalities.