"I have never regretted my decision. It's been lots of hard work to get to where I am today, but also lots of fun, and very rewarding work."
Between 1983 and 1987 Mr Farnworth was customs attache at the New Zealand Embassy in Tokyo, and on his arrival he was told by Japanese officials he would be more important than the ambassador. After the Customs Service restructure in 1997, Mr Farnworth left the policy division in Wellington and began running the Tauranga branch with a team of eight staff, which has since grown to 14.
In the next decade he oversaw the integration of electronic documentation and the introduction of X-raying at the Port of Tauranga gates.
Mr Farnworth said the focus of Customs had changed significantly since his early days.
"We went through the 1980s as an enforcement department, then trade facilitation in the 1990s. But from September 11, 2011 our focus moved to border protection and
our communication and intelligence systems have become far more sophisticated."
Under Mr Farnworth's watch there had been a number of large seizures of drugs.
That included the discovery of 35 litres of liquid methamphetamine worth $35 million in a cargo vessel in 2007 and early this year Tauranga Customs staff were involved in the seizure of $176m worth of P in a shipment from China.
Mr Farnworth said these types of big busts made the quieter times worthwhile.
In 2007 he was made a Member of the NZ Order of Merit in the New Year's Honours' list for his Customs work.
"It is one of my proudest moments. It was great to be recognised for doing something I have loved and been passionate about doing all my adult life," he said.
Mr Farnworth said he planned to spend more time playing golf and with his grandkids when he finished up.
Taking over the reigns as port manager is current chief Customs officer Jamie Hickey,
the son of former television weather man Jim Hickey.
Mr Hickey said Mr Farnworth was the "best boss and mentor" he had worked with.