The legislation to increase funding for the International Monetary Fund has caused problems for more people than members of Congress. It has left Dennis Thomas, assistant treasury secretary for legislative affairs, with an unusually busy workload.

In the midst of the IMF funding battle, Bruce Thompson, Thomas' principal deputy, was promoted to assistant secretary for business and consumer affairs. Thompson took over the job just as banking deregulation legislation was coming to the fore.

When Treasury sent the bill to Capitol Hill, it also set up a special committee to meet with groups interested in the legislation. Thompson is now in charge of the committee, and has arranged 13 interest-group meetings in the past few weeks.

In addition, Lyn Withey, another principal staffer in the office of legislation, moved to Alaska days before the IMF vote.

"Thomas has had to carry the ball on IMF pretty much by himself," a Treasury spokesman said. As Treasury Secretary Donald T. Regan's principal strategist on the bill, Thomas has met with all members of Congress in the past two months--in addition to his other duties. * * *

COMPUTERMANIA . . . The word is out: Regan loves computers, a carryover from his days as chairman of Merrill Lynch, Pierce, Fenner and Smith Inc., a spokesman said. The secretary has a console and keyboard on his desk so that he can check the activity of the financial markets and currency fluctuations. All the assistant secretaries have computers, too.

"It started with Regan and it's working its way throughout the department," the spokesman said.

To help move more computers into the department, including such divisions as the Internal Revenue Service and the U.S. Customs Service, Regan has appointed two assistant secretaries to head computer-related offices.

Richard Shriver is the department's new assistant secretary for electronic systems and information technology. His job is to review all of the department's information systems and modernize them.

And Carole J. Dineen has been named the new assistant secretary who will oversee all of the department's debt management operations, monitor the government's check-writing functions and keep track of all government expenditures. Her mission is to modernize the data processing and computer aspects of fiscal management to bring the department "into the 20th century," a Treasury official said.