Lee has seen near-daily protest rallies since early May, sparked by a public concerned over mad cow disease that later turned to a broader attack on his
The cabinet offered to resign en masse a month ago as protests intensified. There had been speculation in local media that Lee might also sack his foreign and finance ministers.
Lee, who scored a landslide win in a December election, said in an interview with Japan's Kyodo news agency on Sunday that if protests continue, it would be a "detrimental" factor dragging down Asia's fourth-largest economy.
South Korea recently slashed its 2008 economic growth target to a three-year low of 4.7 percent, from 6 percent previously, as commodities-led inflation bites into consumer spending and corporate investment.
Too Little, Too Late?
The cabinet change was the latest in a series of efforts by Lee to stop the protests and check the slide in his popularity, including repeated televised apologies and the removal of all his top aides, but analysts saw the moves as too little too late.
Lee will not be able to push through reforms such as privatising state-run firms and mortgage debt relief for low-income households unless he can win back public support, analysts said.
"It is entirely possible to win back public support," said Jeong Chansoo, executive director at Min Political Consulting. "But this president has lost his appeal with the public and unless he wins that back it will be difficult."
The new leader of the opposition Democratic Party said the shake-up fell far short of the overhaul of the cabinet's economic posts needed to make up for the administration's failure to manage inflation and tackle high energy prices.
On Saturday, about 50,000 people protested peacefully in Seoul against the beef deal and Lee's policies, far smaller than the half a million organisers had hoped for.
On Sunday, protesters could not rally enough people for a street march through central Seoul for the first time in more than a month, in what analysts said may be a sign that mass street rallies are dying down.
Jeong at Min consulting said that does not mean Lee will be able to get on with his economic reforms immediately.
"But soon we will have a situation where the economic condition must change, and when that happens the public will be calling for those reforms before he does."