A declining market in the ACT was behind the multi-national ad agency's decision to shut shop in the city.

The business' eight staff were informed of the decision this week.

General manager Tony Mansfield said a small, declining market in Canberra and reduced client budgets in the government and private sectors had influenced the decision.

"The number of clients and the number of opportunities in Canberra are limited," he said.

"The Canberra work is very project-based, not contractual, so the revenue is less predictable."

Mr Mansfield said the agency was doing everything it could to support its 10 to 12 clients affected by the closure.

Grey Group Canberra is part of a global organisation with offices across the world, including in Sydney and Melbourne. The agency forms part of advertising conglomerate WWP.

Mr Mansfield said the broader global market influenced where the agency invested resources.

"There are different growth markets around the world; South America and South-East Asia and emerging markets in China and India where they're obviously growing important markets where resources and efforts go," he said.

"It's about relocating efforts and resources to where rewards will be maximised. Unfortunately that's no longer in Canberra."

Mr Mansfield said his team had been very positive and the broader response had been one of understanding and support.

"Yes, it's a sad time but at the same time I think people realise new opportunities will open in new forms," he said.

"All our clients have been very understanding and appreciative of the work Greys has done over 40 years. It's a long time and a lot of clients have been with us over that time.

Former Greys general manager and Coordinate director Warren Apps, who worked at Greys for about a decade, said the news had come as a shock.

Mr Apps dismissed views his departure from the company a couple of years ago had influenced the closure.

"I don't look at this with any sense of achievement, that me leaving precipitated this," he said.

"Every agency is stronger than its leader. I think it's a question of circumstance."

He said the market had changed dramatically over the past two years but remained robust.

"I don't think anyone is completely taken by surprise because we are all pretty well attuned to change nowadays but it's still never nice to have a company pack up its bags and leave the market - it doesn't reflect well on the entire market," he said.

"I'd hate it to send the message ... the market is not strong here. Certainly, our perspective is the market is very strong."

Mr Apps said there had been an increasing desire for government and commercial clients to work with independent agencies due to Canberra-based connections, an understanding of the local market and a perceived sense of ownership.

"Greys, obviously being a multinational, it's perhaps a little harder to develop that local connection," he said.

Mr App was confident the territory's small marketing and advertising industry would get behind clients and employees affected by the closure and soak up the remaining workload.