Mr Sisley, 61, died in a Sydney hospital on Sunday night as a result of complications after surgery.

In his last column for the Central Western Daily, in January, Mr Sisley wrote about the "tedious spot of cancer" in his oesophagus and the three months of "aggressive" chemotherapy he underwent.

Minister for the Arts George Souris was among many who acknowledged Mr Sisley's passion for the arts.

"I want to pay my respects to Alan's family, friends and colleagues, and acknowledge his significant contribution to the arts in NSW, including as the Orange Regional Gallery director for the past 22 years," he said.

"His leadership and passion for the arts has made a great deal of difference to artists, the region and regional galleries across the state, and I'm sure he will be dearly missed."

The gallery's assistant director Brenda Gray said the public sculptures outside the gallery were a major achievement of Mr Sisley's tenure.

"He was wonderful to work with, he was a real character and a highly intelligent person," she said.

"We've been overwhelmed with the sympathy and support of other regional galleries... everyone is shocked by his untimely death."

Orange mayor John Davis said Mr Sisley was a very loyal servant of the council and the art community and brought passion to his role.

"He was highly respected in his field," he said.

"Orange was very lucky to have a man of his ability and quality in our midst, he'll certainly be very hard to replace."

General manager Garry Styles said Mr Sisley's "creativity and dogged determination" made the gallery stand out from other regional galleries in Australia.

"He was never afraid of criticism or to stand up for ideas that might have been unpopular or against the flow," he said.

Central Western Daily managing editor Tony Rhead said staff always looked forward to Mr Sisley's visits to the CWD office to drop off the weekly column he wrote for more than two decades.

"He wasn't afraid to take risks, beyond what you'd expect in a regional gallery," he said.

"It wasn't about him, it was about the visiting curators and art across the region."

Dr Andrew Flatau, a writer/curator affiliated with the gallery, said Mr Sisley regarded his CWD column as an important part of bringing art - and the value of art to the community and was the region's greatest advocate for community engagement in art.

Mr Sisley gave Dr Flatau the opportunity to curate exhibitions and write about art.

"He was also internationally recognised for his support of talented outsider artists, whose work would not otherwise be shown to the general public," he said.

"From a personal perspective, I will sorely miss our discussions about art and philosophy."

Artist and TAFE arts teacher Victor Gordon said Mr Sisley was adored by students at TAFE where he taught art history.

"He gave students the opportunity to learn with a gallery director," he said.

"I had two major shows at the gallery and he made life very plesant for me.
"We're absolutely devastated his life was cut short."

Friends of the Regional Gallery president Ros Kemp said Mr Sisley brought high intellect, great knowledge, and willingness to explore art from diverse sources to the artistic and intellectual life of Orange.

"Alan was a man of many parts, very down to earth, with a capacity to talk to everyone, and communicate his passion for art and life generally," she said.

"His enthusiasm was infectious, and his work for the gallery in selecting exhibitions, curating touring exhibitions, and purchasing works for the permanent collection has made Orange Regional Art Gallery significant both locally and nationally."

ALAN Sisley became the Orange Regional Gallery's third director when he was appointed to the role in 1991, five years after the gallery opened in 1986.

While working as the gallery's director, Mr Sisley was also the president and a board member of the Regional Galleries Association.

He studied philosophy at the University of Otago in New Zealand and later fine arts at the Australian National University in Canberra.

Mr Sisley worked in a commercial gallery - the Australian Gallery - in Sydney and as director of the Hamilton Regional Gallery in Victoria before moving to Orange.

He was credited with developing the Orange gallery's strong reputation for outsider art.

When the gallery's 25th anniversay was celebrated, Mr Sisley spoke about art being for sharing and seeing.

Mr Sisley is survived by his wife Caro and sons Clive and Henry.

His funeral will be held at St Michael's Anglican Church at Vaucluse on Friday at 11am.

A date is yet to be set for his memorial service in Orange.