The dreams of builders who developed the $100 million Omni International complex of offices, retail and hotel space here may have been broken by financial problems that almost brought about an auction-block bankruptcy sale earlier this month.

But the folks across the street at Atlanta's young convention arena, the Georgia World Congress Center, have not felt a ripple from the economic malaise of which Omni is the most striking example - an overbuilding of this city in recent years.

Although Atlanta remains in the midst of recovery from economic recession, the convention business has been booming ever since the $35 million World Congress Center opened late in 1976.

In fact, the center has been so successful that government and business leaders are drawing up plans for a major expansion in the near future.

Built by the State of Georgia, the convention center has 350,000 square feet of exhibition space in an overall 718,000-square-foot complex. Visitors enter through a huge two-level center gallery that runs the length of the center and connects all meeting rooms, offices, cocktail lounges, newsstand, an international telephone center and restaurant.

In 19 months, the complex has attracted more than 1:15 million persons to Atlanta - most of them for shows and conventions that otherwise would have gone elsewhere. Recent visitors have included choral groups from public schools in Washington, D.C., who participated in music competitions. They also added to the local tax base with side visits to the suburban Six Flags amusement park and Atlanta Underground, a financially troubled maze of shops on the post-Civil War street level below today's avenues.

According to World Congress Center figures, each convention visitor stayed here an average of four days and spent $68.75 a day during the center's first 19 months. Some $9.5 million has been added to the state treasury, while the city and transit authority have benefitted from additional, specific taxation.

Advance bookings for 1973 point to a 25 percent increase in convention business this year, and one meeting has been scheduled for 2010, the Atlanta Journal and Constitution reported.

Based on these developments, convention promoters are planning to ask the Georgia legislature to approve another $45 million to $50 million for immediate construction of an adjacent 718,000-square-foot hall, to be connected by tunnels under a railroad track.

"We had thought we wouldn't be going to the legislature asking for expansion money until at least 1980, but we'll go next year because the demand for more room is tremendous," said Gene Dyson, chairman of the center and president of the Georgia Business and Industry Association.

Georgia is financing the original building with a 20-year bund issue that is being paid off at a rate of $2.8 million a year. The center was able to reject a $500,000 state subsidy designed to help meet a first-year budget simply because it wasn't needed to balance the books.

Still the convention center itself has not led to rapid development on nearby city blocks. Many perosns attending conventions here stay at hotel blocks away, within easy access by a downtown bus service. There remains a visible deteriorating commerical center between the luxury of Peachtree Center shops or hotels and the World Congress Center.

The Ommi complex next door is busy during the day as shoppers and visitors shop by boutiques and restaurants or watch ice skaters in a rink at the bottom of a multistory open court. But one-third of the retail space is vacant as is one-fifth of the office space.

Owners of Omni are working on a plan to reorganize the center's $90 given six months to do the job by their creditors.