MR Alexander Arena, the Australian who is to head Hongkong's proposed new Office of the Telecommunications Authority (OFTA), sees himself as an agent of change rather than a traditional public servant. But Mr Arena, known to friends and colleagues as Alex, wants the 230 Post Office staff who will be transferred to his office to take that not as a threat but as a promise of good things to come. He moves to Hongkong this week, fresh from overseeing the deregulation of Australian telecommunications. That had brought major benefits to customers in lower prices and better service, he said. Hongkong customers could expect to benefit too, although not necessarily in those same ways, Mr Arena said. ''In Australia it is no longer the era of telephones 20 years ago when you could have any phone you wanted as long as it was black. The very threat of competition produced results,'' he said. ''In Hongkong the mobile market shows the benefits of competition. Hongkong consumers can rightfully ask why they cannot see similar benefits on the fixed network. ''But I don't think I have to teach Hongkong much about competition.'' Mr Arena knows that competition can produce problems too. He will be alert to them as he oversees the introduction of competition to Hongkong's local telephone market when Hongkong Telephone's monopoly on basic services expires in 1995. ''You have got to be prepared to monitor quality of service to ensure it does not deteriorate in the light of price competition,'' he said. And he warned there could be tough times ahead for Hongkong Telephone: ''It will face some difficulties in the evolving climate.'' As the territory's telecommunications regulator he will be monitoring those difficulties. Goals alone were not enough, he said. They had to be carefully implemented. ''One of the policy objectives is to create a better set of outcomes for consumers and telecommunications.'' Mr Arena, who was born in Malta and migrated to Australia at the age of four, is a public policy specialist. He grew up in Sydney and studied engineering at the University of New South Wales, later completing a Melbourne University Master of Business Administration. He entered the public service even before graduating, beginning in aviation policy and advancing to oversee the deregulation of aviation in Australia and the setting up of the Federal Airports Commission and the Civil Aviation Administration. ''My career has been one of doing a job that needs to be done, often moving to a different one in periods of time ranging from 18 months to two years and being thrown another challenge,'' he said. ''I don't see myself as a traditional public servant. I am often an agent of change.'' In 1987, he turned his attention to telecommunications and two years later became a member of AUSTEL, Australia's telecommunications watchdog. But although Australians are only now starting to feel the effects of deregulation and the introduction of competition, for Mr Arena the early challenge has gone from his job. ''One of the things that is quite difficult for many observers outside the industry to appreciate is that a lot of the preconditions for telecommunications competition - mobile regulatory arrangements, a competition safeguards regime, for instance - havebeen in place for two years,'' he said. ''The take-up of competition is happening because those fundamental building blocks were in place. ''To the extent that is the difference between AUSTEL, which is moving into a more mature phase, and OFTA, which is still at the ground-breaking phase.'' Mr Arena admitted it was no surprise to be asked to help Hongkong's telecommunications industry break that new ground. ''We have had regulatory contact with Hongkong since AUSTEL was started and I have had cause to visit Hongkong,'' he said. ''Through that sort of contact they have come to know what we are doing in Australia so I suppose it is a fairly natural step that they might look this way in filling the post.'' It had all happened fast - a surprise to those who thought the public service wheels grind slowly, Mr Arena said. But he was unsure whether he would have applied if the job had been advertised late last year instead of being offered to him. For the close-knit Arena family - Alex, his wife, Carmel, and their two young daughters, Vanessa, 12, and Livia, nine, the move to Hongkong will bring dramatic changes. Their home on a country block outside Melbourne will be exchanged for an inner city flat. Mrs Carmel Arena, a ceramic potter, will have to put her own business on hold. Mr Arena will work as a consultant in the economic services branch until OFTA is set up. Then comes a three-year contract as director general of OFTA. ''One of the first tasks will be the logistics of the bifurcation of the Post Office and the dislocation effect that people have when they go through that sort of thing so there will be a need to settle that down.'' After that his key objectives, as set by the Hongkong Government, will be to introduce competition to the domestic market and to implement the new price cap arrangements. ''I will be looking at how the consumer benefits of competition are carried through and how the competition policy safeguards are implemented,'' he said.