A lawyer and former Canberra insider who worked for state MPs and federal cabinet ministers has been confirmed dead after he disappeared in Sydney's Chinatown while on a work trip.

Nicholas Mowbray had failed to turn up for the second day of a professional event he was attending in the city last week, and his family, friends and colleagues were unable to contact him.

A policy adviser with extensive experience in politics, government, and parliamentary and legislative processes, Mowbray had spent 15 years in Canberra advising Greg Combet and Pat Conroy.

Mowbray was last seen in Chinatown, in the inner suburb of Haymarket, on Wednesday, May 20, at about 9pm.

NSW Police confirmed late Tuesday afternoon that Mr Mowbray had been located, but did not release any further information. Family members subsequently told the Daily Mail their 'much-loved' relative had died.

There are believed to be no suspicious circumstances. 

At the time of his disappearance, the 43-year-old was described as 175cm tall (5ft 9in) of medium build, with brown eyes, short grey hair, and unshaven.

Police said he was known to frequent Lake Macquarie, the Hunter Valley and Newcastle.

Mowbray, who had travelled down from his home in Cardiff, in the Hunter Valley, to attend the work event, was employed as a policy officer in the mayor's office at Muswellbrook Shire Council at the time of his death. 

Chinatown and Haymarket are considered among Sydney's most vibrant neighbourhoods, with multiple late-night food outlets that attract throngs of visitors. 

When Mowbray did not appear as expected on day two of his work event last Thursday, friends reported that 'nobody has heard from him or been able to reach him'.

'People who know him are worried,' a friend was quoted as saying before news broke of Mowbray's death.

'NSW Police are already investigating and have put out a public appeal, but so far there has been no sign of him.'