An itching question.

Recently I have been reading the book Consider Phlebas by famed scottish writer of both general and science fiction Iain M Banks. The book is one of his six and soon to be seven Culture novels dealing with the semi anarchic (spelling?) alien civilizations by the same name found in our own milky way. My question is whether or not his SF should be considered Hard SF? The writing is extremely technical but I am still unsure. If you have any of the six books those being Consider Pheblas, The Player of Games, Use of Weapons, Excession, Inversions and Look to Windward tell me what you believe the answer to be!