The much-maligned U.S. dollar yesterday soared to its highest level against the West German mark in more than two years, prompting Chancellor Helmut Schmidt to complain that the dollar is overpriced and the mark too cheap.

In recent years, the standard criticism from European officials -- especially the Germans -- was the other way around: They said the dollar was so cheap or undervalued that it required massive support by European central banks through intervention in the foreign exchange markets, inflating their domestic money supply. The United States was following a policy of benign neglect of the dollar, Europeans complained.

Moreover, the old argument was that a cheap dollar gave U.S. goods a competitive advantage against European goods priced in higher currencies. But yesterday, a Reuter story from London said that "a strong dollar makes imports from the United States more expensive for other countries and thus aggravates their inflation."

Meanwhile, gold plummeted below the $600-an-ounce level yesterday, and dealers attributed the drop to "extreme technical pressure from interest rates," United Press International reported.

In Zurich gold fell to $604.50 an ounce from $617.50. In London the close was $607.50, down from $616.50.

[But in New York gold plunged to $594.75 an ounce from $615 Monday. Silver closed at $16.65 an ounce, down from $17.50 the day before. The Comex settlement price for gold was $591.30 an ounce, down from $613.20, and the silver settlement price was $16.50 an ounce, down from $17.41.]

In an interview yesterday, Assistant Treasury Secretary C. Fred Bergsten told The Washington Post that the dollar would continue to show "underlying strength" because of a striking improvement in the U.S. current account, which reflects the international balance for trade and services.

"For three straight years, we have had a balance or surplus in our current account at a time when practically everybody else except OPEC [the Organization of Petroleum Exporting Countries] is in deficit," Bergsten said. At the moment, the dollar also is benefiting from a dramatic run-up in interest rates. As Schmidt noted, with the American commercial banks' prime rate at 19 percent, the differential in U.S. rates over West German rates is about 10 to 11 points, which attracts investment money here.

Bergsten also cited the unsettled political situation in Europe. Fear of a Russian invasion of Poland, in particular, adversely affects the mark. The special problems for the mark -- in addition to a general deterioration of the German economy -- can be seen in the continued strong relationship of the yen and the pound to the dollar.

Bergsten said that the outlook for the U.S. current account in 1981 is favorable despite rising prices for oil. Historically, this may be the key to the international exchange market's evaluation of a currency, according to Federal Reserve Board member Henry Wallich.

In 1978, the United States suffered a current account deficit of $15 billion at a time when its oil bill ran to $45 billion. But in 1979, with an oil bill rising to $60 billion, the U.S. shaved the current account deficit to just about $1 billion. Then this year, with the oil bill rising to an estimated $80 billion to $85 billion, the current account is expected to be just about even or show a slight surplus.

"Our export competitiveness has been truly impressive," Bergsten said. He noted that the United States also has been able to cut back steadily on oil import volume so that the damage caused by massive OPEC price increases has been held in check. Thus, the dollar cost of oil exports between 1979 and 1980 was up by about one-third, although the price of oil imports doubled.

Schmidt's remarks were made in Bonn after a meeting with Italian Prime Minister Arnaldo Forlani.