Last year I went to southern Cyprus for a week and during that week visited the northern part for a day, no problems at all when re entering the southern part. (whilst I appreciate that the visa was only stapled in my passport) Many people make this trip including Greek Cypriots so cant really see why you should have any problems, Also my brother has visited Turkey and the southern part of Cyprus and has not had any problems. (stamps in Passport) If in doubt try the Cypriot Embassy, also we must remember that they are in Eurpoe now and I am unable to see how they can refuse your entry...Open to further info thought..