Australia's two-month-old Labor government is quietly charting a new economic course with a more restrictive approach toward foreign investment as it struggles to hold together a fragile agreement business and labor leaders approved at a recent "national economic summit."

Although the government denies any official change of policy on foreign investment, it has rejected each of six applications put to the Foreign Investment Review Board so far by foreign firms wishing to buy into Australian ventures. The Labor Party administration of Prime Minister Robert Hawke also reversed a decision by the previous conservative government to allow 10 foreign banks to begin commercial operations here.

In its latest rejection of a foreign investment bid, the government spurned an application by a South Korean firm to buy 25 percent of a pipeline project in Queensland. The state government there, which badly wanted the investment, sharply attacked the decision.

The government's wage-restraint policy has also been under attack, as maverick labor unions press demands for pay increases that threaten to erode the government, labor and business consensus that emerged at last month's economic summit here.

In a bid to hold together the accord, Hawke, himself a former trade union leader, pleaded with union members last week to restrain their wage demands and allow the government to pursue its "noble objectives" of stimulating the recession-ravaged economy and creating jobs.

Critics accused the government itself of undermining the summit's consensus on wage restraint by agreeing to an effective pay increase for about 130,000 construction workers through new "site allowances." The allowances are meant to compensate for such inconveniences as exposure to the elements.

The strain on the summit agreement reinforced the impression among some segments of the Australian press that the Hawke government, after an impressive fast start, is starting to founder on the same economic shoals that stymied the administration of former prime minister Malcolm Fraser.

Sen. Donald Chipp, the leader of the Australian Democrats Party, hailed the four-day economic summit of 100 business, government and labor leaders as "an outstanding success in political, social and economic terms." He said its most significant result was "a unique agreement" between management and the union movement.

Chipp, whose small but influential party campaigned for the March 5 national election with the slogan, "Keep the bastards honest," said the government might not be able to enforce the summit agreement perfectly. But he said that "if the thrust can be maintained" and "outrageous wage demands" curtailed, it would go a long way toward solving Australia's economic problems.

The leader of the parliamentary opposition, Andrew Peacock, dismissed the summit, however, as a "substitute for action." He said the government is in a "state of confusion on wages policy" and is giving "greater emphasis to close relations with unions than to an appropriate economic policy."

Arguing that Australia has priced itself out of international markets because of high labor costs, Peacock said it was essential to hold down wages for the rest of the year.

For the last two years, wage increases have been running at about 17 percent a year, considerably above the inflation rate of 11 percent to 12 percent.

The government presently supports a "wage pause" through June, followed by a 3 percent to 4 percent national increase later in the year and full quarterly adjustment to the inflation rate next year. The inflation rate of about 9.2 percent since the six-month wage freeze went into effect would not be made up.

At any rate, this was the understanding that emerged from the economic summit.

But some unions, notably the Builders Laborers Federation, have been chipping away at the agreement by pressing for shorter working hours, higher wages and "catch-up" payments to make up for inflation.

Dealing with the unions is often difficult because there are nearly 350 of them for a work force of 6.7 million. At least 25 unions operate in the Port of Sydney alone, and if any one of them goes on strike the whole port risks being shut down, diplomats said.

Scheduled freighters have spent one-third more time in Australian ports than planned because of frequent labor disputes, the diplomats said, and strikes have given Australia a reputation as an unreliable supplier in some countries. For example, Japan has seen its coal imports interrupted several times because of strikes by one or more of the 35 unions involved in getting coal from the mine to the port.

While the new government has its hands full dealing with unions and wages, it has been relieved of obligations to press ahead with all its election promises--including a $1 billion tax cut--because of the $9.6 billion budget deficit--$4 billion more than expected--that was inherited from the previous government.

At the same time, the government has managed to dispel the financial panic that preceded the election, when $2.5 billion fled the country within several weeks. A 10 percent devaluation two days after the election stopped the outflow, and now practically all of the money has returned, economists said.