South Korea's new government plans to open the doors wider to foreign invest and management as part of a widespread industrial restructuring intended to revive a stagnant economy that has gone from boom to bust in less than two years.

Government planners said this week that foreign companies will be offered a chance to invest in more Korean industries and will be permitted a greater share of ownership in companies they form here.

They said details will be announced soon to permit overseas investors to have complete ownership of some companies in South Korea for the first time. The list of industries for foreign investment will be expanded, they said.

The move toward easier foreign ownership caps an economic revival campaign that already is forcing widespread changes in the industrial structure here. major domestic corporations are being compelled to divide their spheres of activity under a tough government program designed to increase efficiency and competitiveness.

There are signs that, will its political opposition crushed, the new government of President Chun Doo Hwan is turning its attention to economics and this country's sagging business activity.

After more than a year of turmoil -- including the assassination of President Park Chung Hee -- the economy is at its weakest point since the preboom era of the 1960's. After posting annual growth rates of 10 percent or better during the past decade, the gross national product this year will be minus 1 percent or minus 2 percent, planners say.

Exports have declined so quickly and so deeply that experts project a deficit in current accounts this year of more than $5 billion.

The government announced some short-term policy guidelines on Tuesday to spur exports and domestic demand. There will be greater reliance on export loans and credits, a modest letup on real estate taxes to stimulate housing and a lowering of interest rates in savings banks to put more money into domestic consumption.

Officials would have preferred a program offering more stimulus but acknowledged they still are restricted by the need to curb the bout of inflation that began nearly two years ago.

They are looking more to bigger foreign investments and to a basic overhaul of domestic industry to get the economy back on track and are predicting a growth rate of 5 percent next year and 8 percent in 1982.

Foreign investors long have objected to restrictions placed on their activities in South Korea, and some easing of those restrictions was being considered last fall when Park's assassination threw the country into turmoil and brought new economic adventures to a halt.

Officials said the major change will permit foreign investors to own a larger share of industries they develop here. In the past, they have been prohibited from owning more than 50 percent, and usually it has been considerably less. The new rules will permit ownership of more than 50 percent and will permit a 100 percent ownership in some cases involving high-technology industries.

In the past, some industries have been out of bounds to foreign investors, and the new rules will expand the list of those in which foreigners can participate.

The government has shown considerable displeasure with many major industries and in the past few weeks has set in motion a major reorganization through which it is forcing some of the biggest corporations to surrender their position in key industries.

The government wants more specialization and less competition in key industries, such as power generation and heavy manufacturing.