Boutique Australian law firm AdventBalance has brought its unconventional business model to Hong Kong with the opening of an office in the city.

The Sydney-based outfit, which operates as a company rather than a partnership and which charges clients fixed-fees only, said its decision to open in the Asian financial hub comes amid heightened demand for its services in the region.

Founded in 2008 through a combination of Sydney's Advent Lawyers and Perth's Balance Legal, it now boasts offices in Sydney, Perth, Melbourne, Singapore and Hong Kong.

Unlike a typical law firm, it seconds senior lawyers to clients' offices for specific projects and transactions; agreeing a fixed payable amount for the period and hours involved.

With 100 lawyers in Asia Pacific, core practice areas extend across corporate and commercial, technology telecommunications and IP, banking and finance, regulatory and compliance, litigation, energy and resources and property and construction.

Managers believe their firm is growing quickly while traditional firms are struggling due to the decline of hourly rates and the rigidity of traditional partnerships.

"We find (our model) to be a far more progressive and flexible structure [than the partnership model]," said the firm's managing director for Asia, John Knox.

"The firm also operates in a very different way to the traditional law firm partnership. All of our lawyers have a combination of private practice and in-house experience, they work from our clients' offices on secondments and we use a completely fixed fee model, not hourly rates.

"We set up in Hong Kong due to strong demand from our clients with a presence there."

The Hong Kong office, which will be led by newly-hired lawyer Lesley Hobbs from next week, is based on Wellington Street in Central; a popular restaurant area with expats and tourists but a far cry from the Grade A office space occupied by the likes of magic circle and big US firms.

Knox said a prestigious location is not as important for his firm since it performs a back office function rather than a setting for client visits.

"We are cost conscious and try to keep our overheads as low as possible so we can pass those savings through to clients," he said.

"Our office on a day-to-day basis is for our management and administration staff as all of our lawyers work at our clients' premises when needed."

He added that the firm is currently hiring in Hong Kong, and will look for strong mid-level lawyers with a private practice and in-house background.

Managers are currently not planning any further office openings in Asia but said they would continue to evaluate opportunities when they arise.