Architects of a new generation of modern buildings are offering workers ''living spaces'' and ''lounge'' facilities to make them feel at home, often replacing the traditional desk and chair.

The trend towards activity-based work or ''hot desking'' - now firmly entrenched in Australia's corporate sector - will gradually evolve into ''informal'' work spaces, says David Gianotten a director of OMA Hong Kong, the architects behind the iconic Shenzhen Stock Exchange and the new CCTV headquarters in Beijing.

Modern workplaces have been transformed over the past decade by activity-based working, where employees share desks and collaborative spaces, allowing businesses to save space and cut costs.

But new office designs were shifting towards pseudo ''living rooms'' and more informal interiors, Mr Gianotten said.

''Instead of hot-desking it becomes simply a 'hot' environment, or 'living room' environment is a term that a lot of people now use, where you can choose your own way of working and are not locked to a desk any more.''

''You see more and more very informal spaces that are full of couches and soft furniture where people work a full day because they are used to lounging and lying around when they work with their computers,'' Mr Gianotten said.

Not surprisingly, technology companies were at the forefront of the trend, but conservative businesses such as management consultants McKinsey & Company were also adapting, he said.

Architects were being challenged to design for contradictory needs.

People want choice, flexibility and the ability to influence their work space, while at the same time there was a push to ''more collaborative spaces, informal meeting spaces, more space for people just to encounter each other'', Mr Gianotten said.

''If you look at where it is heading currently, it is heading towards spaces without a desk. There are now in many office designs areas where you can be on a treadmill while you do your phone calls, or sit on a high stool with a moveable table in front of you.''

Australian businesses were quick to adopt activity-based working and are likely to move as fast towards informal spaces.

''We're one of the leading markets in the world for that type of space in the workplace,'' Hassell Studio principal Steve Coster said, citing recent home-like interior designs for advertising agencies George Patterson Y&R and Clemenger BBDO.

How far businesses took the idea depended on their circumstances, but it was driven by a recognition that employees spent a lot of time in the office and comfortable informal spaces helped them perform at their best, Mr Coster said. ''The more you can do your work from anywhere, the more important it is when you get together that you have high-value time,'' he said.

The shift did not necessarily require businesses to use more floor space. Instead desk-related areas were more concentrated while the ''unorchestrated'' part of the office became larger, Mr Gianotten said.

Design firms were employing behavioural specialists to better understand how to create interiors that encouraged creative interaction among employees, he said.

David Gianotten will speak at the Design Speaks: Work Place/Work Life Forum on July 14.