President Reagan has asked the Treasury Department to study the possibility of minting a general purpose gold coin to replace the South African krugerrand for coin collectors.

The government has not minted a gold coin since 1933, Treasury Department officials said. The request for the study came after Reagan on Monday said he would take steps to ban imports of the popular krugerrand gold coin as part of a group of sanctions against South Africa.

The move was taken on behalf of coin collectors, officials said. Treasury Secretary James A. Baker III has been ordered to report to the president within 60 days on the "feasibility of minting an American gold coin."

Both the House and the Senate in the past have supported legislation authorizing a U.S. general circulation gold coin. The House recently passed legislation to impose sanctions against South Africa which ordered the Treasury to begin minting a gold American Eagle coin by Oct. 1 next year.

The coin would have the United States seal with the American eagle on one side and on the other side the image of Liberty that was on some gold coins minted in 1908.

The Senate has not yet acted on sanctions legislation that would also create the American Eagle coin. The Senate bill calls for the coin to be classified as bullion, meaning that its worth would be determined by the market price for gold on a given day.

The House consumer affairs and coinage subcommittee has said that sales of the proposed eagle coin could exceed 2 million ounces a year, compared with the sales between 3 million and 4 million ounces of krugerrands, the Canadian Maple Leaf and the Mexican gold peso in the last six years.

Treasury officials said Baker has not yet decided who would study the coin issues but it would involve the office of U.S. Treasurer Katherine Ortega.

The Treasury has sold gold medallions, the official said. However, the president specifically requested that the Treasury study the feasibility of selling coins, not medallions.

Some of the issues to be covered under the study are whether such coins are marketable and how they would be sold, the official said.

The United States recently issued limited edition gold coins. Before the 1984 Olympics held in Los Angeles, the United States minted 570,000 commemorative gold coins. The $50 coins sold for $352 each to help raise money for the games.

The Treasury also plans to issue a $5 gold piece this fall to be sold for $175 each to help raise money to renovate the Statue of Liberty.