Gold prices, which plunged on Monday to their lowest levels since April, recovered today, but analysts said the rally is temporary and the price of the metal should continue to decline in the weeks ahead.

On the New York Commodity Exchange gold closed at $494.70 an ounce, up $12.70 from its Monday close.

At the same time, the dollar continued to gain against most European currencies although it declined against the British pound.

Reports from Europe said that gold purchases by the Soviet Union, South Africa and central banks that hold the precious metal in their reserves helped push the gold price back up after it opened up the trading day in London at $482 an ounce, $11.50 lower than it closed in England Monday.

The price rose throughout the day in London. At the afternoon fixing it was $486.25, and in late trading it was about $488.

When trading opened in New York, the price was $490, and it climbed another $4.70 before the Comex closing bell.

"Nevertheless, a decline is still the general trend for gold," according to Leslie Deak, executive vice president of the gold trading firm Deak & Co. He said that the factors that have caused the price of gold to decline nearly 20 percent since the beginning of the year continue to hold sway. The day before Christmas gold was $606.50 an ounce in New York.

"High interest rates make gold an expensive commodity to carry," he said. Those same high rates make it attractive for individuals to put their funds in investments such as Treasury bills and money market funds. Deak said that people still "are willing to bet that the Reagan administration can seriously attack the inflation problem. As long as people believe that, gold will not be an attractive investment."

Investors long have held gold as both a hedge against inflation and a store of value during times of international tension.

However, Deak said, within six months, when it becomes apparent that the Reagan administration's ability to make substantial budget cuts is limited, gold again will become an attractive investment.

In European trading the dollar started the day on the downside but quickly recovered, although it declined against the British pound.

In London a jump of $918 million in Britain's gold and dollar reserves pushed the pound back up from its opening 13-month low against the dollar to a closing price of $2.3515 compared with $2.3490 Monday. Sterling rose to $2.3550 in New York.

In Milan the dollar shot up to set a record at 1,01845 lire compared with 994.45 Monday, and it was trading at 1,003 lire in New York.

In Frankfurt the dollar closed at 2.1495 marks, the best since January 1978 and up from 2.1220. It eased back to 2.1170 in New York.

Other European closing rates (all approximately three-year highs), with late New York prices in parentheses:

Zurich, 1.9465 Swiss francs, up from 1.92375 (1.92); Paris, 4.9625 francs, up from 4.89275 (4.87); and Brussels, 34.50 Belgian francs, up from 34.075 (34).

In Tokyo the dollar surged to 205.15 yen from 203.30, but eased to 203.50 in New York.