Zervos also dismisses the perception there is a drift towards political considerations playing a part in deciding who is and isn't prosecuted.

'Whenever I have conducted my cases - and I don't think that anyone would say anything to the contrary - I've always been firm and fair, I've always ensured that the interests of justice come first. These are concepts, principles that you grow up with as a prosecutor, that become part of your everyday thinking - just naturally. They're not just mere words.

'When you're talking about justice and being fair, you really mean it. It's your lifeblood as a prosecutor. I'd rather tell you what my principles are and you can judge me by the way I do my job, not by the description you give me.'

A veteran of frontline Hong Kong criminal prosecutions spanning two decades - from the brutal assassination by a triad hit squad of a key ICAC witness in one of the world's biggest tobacco-smuggling cases, via complex fraud and corruption cases to pivotal human and constitutional rights appeals - you get the impression Zervos likes to keep things clean by getting his hands dirty.

'I've covered a wide range of cases, from the nasty, to appeals on the fundamental principles of human rights and extremely difficult white-collar crime cases, a 'rich tapestry',' he says.

Zervos 'hit the ground running' as an up-and-coming prosecutor on arrival in the city in 1992. The first thing he did when he took over from Ian McWalters four months ago was issue a note to staff reminding them of their responsibilities to themselves and to the public.

He argues the public is quite rightly increasingly demanding to know more about who is and who isn't prosecuted - and why. But Zervos is adamant the reminder wasn't needed because his foot soldiers in the Department of Justice's prosecutions division had forgotten their mission.

'I think we all need to remind ourselves all the time. Remind ourselves of the fundamental principles that govern our work as prosecutors, or in any field. I thought it was necessary to reinforce my position, my own vision and ideas of the position. It's a reminder that I'll keep on making, it will never stop,' he says.

'Law and order is important because it provides the community with stability, with peace and prosperity. The criminal justice system is one of the essential features of ensuring that we maintain the rule of law. The criminal justice system must function effectively and properly and we as prosecutors are probably the main players in that regard. It is an onerous duty we are performing for the community.'

Zervos - the Melbourne-born son of a Greek immigrant father and second generation Greek mother - joined the government as a counsel and became deputy director of public prosecutions in 2008. He was a senior prosecutor specialising in major fraud cases in Australia before coming to Hong Kong.

One of his main concerns is the treatment of young and first-time offenders.

It is an area of his work the new DPP has long held is a vital area of a prosecutor's job: 'It [dealing with young offenders] comes from some very sound principles. These principles have been with us for a very long time and those of us who practise criminal law are aware of these principles.

'Stating these principles is one thing, putting them into action is another, and we have to positively put them into action. We are keen to ensure that first-time offenders are steered away from crime, not into it.'

Those who break the law for the first time - whatever their age - are also on his radar.

'It may not be necessary to secure a conviction against a particular person - thereby breaking their spirit - but deal with them by binding them over and not recording a conviction. This serves the interests of justice and gives the offender an opportunity for a second chance,' he says.

'We have to realise we are impacting on people's lives and approach our work as prosecutors with a high degree of seriousness and care. There is no greater sense of satisfaction for a prosecutor than to make a decision that results in someone rehabilitating and walking away from crime.''

As he gets to grips with life as the city's top prosecutor, Zervos is not interested in talking about the past. While he would never use the words, there is a definite whiff of the new broom about his demeanour.

'My mind is not occupied by what my predecessors did or didn't do. It's the here and now that's important, and also tomorrow and how we operate in the future,' he says. 'The system is working very well, but there is room for improvement in every corner. Prosecution work is getting more complicated and the criminal justice system is made up of people, and people have their imperfections. It's a changing world, the law is changing. When we talk of efficiency we are talking about keeping up, we have to strive for excellence.

'Laying foundations for the future means not only ensuring that we have a first-class prosecution service today but that we have a first-class system 10, 20, 30, years ahead. Putting the structure and the mindset in place for future development and progression is an important function of a DPP.'

The training of young lawyers and closer co-operation and partnership with the private legal practitioners are also being stepped up as Zervos plans for the future.

Pushed on what he would have done in controversial decisions such as that not to prosecute two bodyguards of Zimbabwean President Robert Mugabe after an assault on news photographer Richard Jones in February 2009, he said cryptically: 'Would I have prosecuted? If it happens again, you'll find out.'

But he added: 'We have to make sure that we get it right. As to how I would have approached the case would have depended on the material and information that was available at the time. I think that in cases of that type you need to be accountable, you need to explain your decision. Whether it was the right decision or not, well, I'll let others decide that.

'But I can assure you that when I am making decisions of that type I will be employing the appropriate legal principles and criteria. Where we can respond, we should respond when we are asked by the public for an explanation. Sometimes, if a matter is before the court or there are particular sensitivities and public interest concerns, we have to be very careful. But I will be striving for more transparency.'

Legal brief

1978 Admitted to practise as a barrister and solicitor in Australia after graduating in science and law from Monash University.

1983 Registered as a barrister and solicitor of the High Court of Australia

1984 Worked with Australia's Special Prosecutor's Office investigating and prosecuting large-scale frauds

1987 Admitted as a barrister and solicitor in New South Wales, Australia

1989 General counsel to the Independent Commission Against Corruption in New South Wales

1992 Joins the Hong Kong government as a counsel

1992 onwards: Department of Justice commercial crime unit and head of appeals specialising in human rights

2003 Appointed a senior counsel in Hong Kong

2008 Becomes deputy director of public prosecutions

2009 Completes master of laws (human rights) at University of Hong Kong

2011 Appointed director of public prosecutions