Dickinson, Mackaman, Tyler & Hagen P.C. may relocate when its lease expires, but the law firm has no definite plans to vacate the Hub Tower.

The firm, which opened its office at 699 Walnut St. in the mid-1980s, is looking for about 20,000 to 25,000 square feet of office space in Greater Des Moines.

“Our lease will be up in April 2012, and it’s not too soon to start thinking about our options,” said Jeff Krausman, a shareholder who is heading Dickinson’s six-person site-selection committee.

Krausman said the way in which law firm spaces are designed is evolving as new technologies allow attorneys to hold meetings via video conferencing and conduct research online.

“I think the goal is to lighten and brighten the law firm environment and trend away from the dark wood and leather-bound books of the past,” he said. “Another significant trend in all law firms has been to create smaller offices for attorneys.”

Now, as Aviva USA and Wellmark Blue Cross and Blue Shield of Iowa prepare to relocate to owner-occupied buildings from leased spaces downtown, Dickinson is taking a proactive approach with hopes of capitalizing on increased competition in the office space market.

The firm has sent more than dozen requests for proposals to local developers and managers of commercial real estate, Krausman said, including the “the usual suspects” downtown.

But Dickinson’s search is not limited to the central business district or to existing developments.

“I think the market is very competitive right now, based on what I’m seeing,” Krausman said, noting that the firm is interested in exploring all of its opportunities before making the “critical decision of whether to stay downtown.”