As he gears up for his new job as chairman of the Senate Foreign Relations Committee, Richard Lugar gives early notice that he will be a strong supporter of President Reagan's diplomacy but will not wave an ideological banner.
His goal will be to build a broader bipartisan consensus on foreign policy, he told reporters in a breakfast meeting Tuesday. Toward this end, his committee will begin, shortly after the President's inauguration Jan. 21, two months of day-by-day hearings on the whole range of foreign policy issues. Administration officials, including US Secretary of State George P. Shultz as well as critics, will be asked to testify at the hearings.
Even while indicating his openness to new ideas, the senator from Indiana, a mainstream conservative Republican, sides with the President on major policies. He made these points in response to reporters' questions:
* The administration should push ahead with research on ''star wars,'' the Strategic Defense Initiative (SDI) aimed at developing a nonnuclear defensive system against ballistic missiles. Despite the anxieties of Europeans, the SDI is what has brought the Russians back to an arms dialogue, and Moscow will go ahead with its offensive arms buildup regardless of what the US does.
* Scrapping of the MX missile would set back the US negotiating posture if strategic nuclear arms talks were resumed.
* Israeli democracy ''is the major thing we have going for us in the Middle East,'' and its preservation is important for US policy. Given Israel's preoccupation with its economic problems and a military withdrawal from Lebanon, this is not the moment for reviving the President's plan for a West Bank political settlement.
* American aid for the contra rebels in Nicaragua has helped disrupt supplies to the guerrillas in El Salvador - the official administration goal - and thereby strenghthened the moderate Duarte government. It has also provided leverage in the diplomatic negotiations with the Sandinista government and diverted Managua from trying to destabilize other Central American countries.
On the subject of South Africa, Senator Lugar's comments reflected the shift of congressional Republicans toward outspoken opposition to the racial policy of apartheid, a significant development on the diplomatic front. The President now understands, he said, that South Africa's white minority cannot go on depriving the black majority of political rights without ''disastrous'' consequences for the world order. It was in part at the urging of Lugar and other senators that President Reagan recently spoke out against apartheid.
Lugar said he did not know what kind of economic or other sanctions might be applied to South Africa. But, he added, he might favor mandatory application of the ''Sullivan principles,'' an agreement whereby American companies doing business in South Africa practice racial nondiscrimination.
Expressing his concern about the problem of verification of an arms control agreement, the new committee chairman said the US had an obligation to look at other options, including the controversial SDI. ''I have not come to a conclusion whether SDI is feasible,'' he remarked. ''But . . . the idea is not so nerve-racking that it has to be bargained away.''
Lugar said that, because of opposition in the House, the Congress is unlikely to restore US funding of the contra rebels in Nicaragua. While he would support such aid, he said, it should not be used to help overthrow the Sandinistas.
The US goal, he stated, should be to negotiate an agreement in which Nicaragua would agree not to try to destabilize its neighbors or serve as a Soviet base. The ''carrot'' to Nicaragua, he added, is that, if it moved to democratize its institutions, the US would be more open to providing economic help.