SEJONG, South Korea—Last October, Yun In-sun left a job in South Korea’s agriculture ministry to join the agency that runs the country’s biggest airport. Ms. Yun feared her family would break up if she didn’t.
The ministry is one of five that will soon move from Seoul to this built-from-scratch city in the middle of the country. Another seven ministries will move here next year, joined by at least two dozen smaller agencies and institutes. Even the national library will eventually move to Sejong.
Even though the move is just 100 miles or so, it is creating upheaval for tens of thousands of government workers, many of whom don’t want to leave the Seoul environs, home to nearly half of South Korea’s 50 million people.
Like Ms. Yun, they are worried about spouses and children who have well-established lives in Seoul. “My husband said we would find a way even if we became a weekend couple, but my kids said they wanted me to quit my job,” Ms. Yun said.
The concentration is the main reason Roh Moo-hyun vowed to build a new city for the national government when he ran for the South Korean presidency 10 years ago. His decision to locate the city on the border of two provinces that tend to swing in elections is considered one of the reasons he won.
After the Constitutional Court pointed out that Seoul is designated the capital by the South Korean constitution, Mr. Roh decided his office, the parliament and several ministries—including foreign affairs, justice and defense—would stay in the city while most others move.
The country’s current president, Lee Myung-bak, in 2009 tried to halt the move and downsize the $20 billion construction budget for Sejong. But parliament voted in 2010 to push it forward, led by supporters of Mr. Roh and politicians eyeing a run for president in the future.
The effect that moving would have on government workers didn’t register in the debate. The South Korean government has forced such transitions before.
In the early 1980s, many government agencies moved from central Seoul to a suburb called Gwacheon on the city’s south side. In years since, the nation’s stock exchange, statistics agency, customs service and national rail system headquarters have moved out of Seoul to other cities.
But a city-out-of-nowhere is a first for South Korea. Today, Sejong is a shell of what it is planned to become. Private builders have erected a few dozen high-rise apartments in lots assigned to them by the government, but most are empty at the moment. About 2,000 people currently live in the city, though that’s expected to jump to about 20,000 early next year as government workers arrive.
On the way into the city, just past the crest of a hill and a billboard that says “Happy Sejong,” the four-lane highway opens up to eight lanes. On both sides, bulldozers and scrapers clear vast tracts of land for more neighborhoods. The government designated areas for hospitals, universities and parks that are years away from completion. It expects Sejong to grow to 500,000 people within 20 years.
"My boyfriend says it looks like Dubai, a city alone in a desert," says Kim Kyeong-eun, who works in the land and transport ministry that will move next year. The couple, who are planning to marry, bought an apartment in Sejong and made a plan for him to visit her on weekends. "In 10 to 15 years, it will become a good place to live, but right now it seems to be difficult."
The government complex is being built in three phases, the first of which is nearly done. Buildings range from three to six stories high. From the ground, they appear like typical office buildings, but their roofs are connected by bridges and will be finished with grass and furnishings to form an uninterrupted pedestrian park.
Commuting costs rise and turnover increases in the initial years after a government relocation, officials say. The ministry that manages government personnel said it is too early to tell how the move to Sejong will affect turnover.
Lee Hye-na left the finance ministry this summer after a little less than two years as one of its English-language interpreters. “If they weren’t moving to Sejong, I think I would have stayed longer,” says Ms. Lee, who now does freelance translation.
For the moment, Sejong isn’t suited for commuters. It’s a 30-minute drive from the major north-south highway and equally far from the nearest station on the country’s high-speed rail system. A trip to central Seoul takes 2½ hours.
The city of Seoul has already experienced an increase in the number of people transferring to its agencies from national ones, though the numbers are only a few dozen.
Lee Hyun-joong left the legislation-writing ministry in March to join the Seoul government’s office of sports promotion. While the city promotes officials less rapidly, Mr. Lee said the tradeoff is worth it because his parents are in Seoul and he thinks it will be easier to find a wife in the big city.
Ms. Kim said she knew she’d have to move to Sejong when she met her boyfriend, but that the prospect of moving seemed “far away.”
"I thought about transferring to another agency that is staying behind in Seoul," she said. "For now, I chose to stay with my work, but I will have more thoughts when I actually get there."
Lee Hye-sun, who also works in the land and transport ministry, said for a while she was reluctant to tell men on dates about her job and that she would have to move to Sejong. She recently decided to live in Daejeon, a city about 15 miles away from Sejong, and said the move has forced her to rethink her strategy for finding a spouse.
"Before I preferred a man who doesn’t work in the government sector, but now I’ve started to think that having a government worker as a husband is not a bad idea," she said. "Watching my co-workers’ families separate because of moving, I started to think that being a public-official couple may be good."
—Min Sun Lee contributed to this article.
Write to Evan Ramstad at email@example.com