President Reagan said yesterday that he is "not scared" to address the financial troubles of the Social Security system, but before the administration comes up with its own "alternatives" he wants the report of a bipartisan commission he established last year.

"We need a solution, but we appointed a commission," the president told reporters. "It doesn't seem to me that this is the place for us to be interfering. We are waiting for the commission to come back and tell us, could they agree on a plan? If so, what, or do they have alternatives? Then we will have alternatives."

After his comments, Reagan received an internal White House briefing on a wide range of questions about the Social Security system, including how to deal with it in the 1984 budget now under preparation, aides said.

Later, administration officials said the White House is "mulling over" some alternatives on Social Security financing and would probably provide some "guidance" later this week to the National Commission on Social Security Reform, which is deadlocked.

"I'm sure we're going to do something," said one White House official, who asked not to be named.

He did not identify what ideas are being studied. But aides said Reagan is being exceedingly cautious because of the uproar that followed his 1981 proposal of deep cuts in Social Security benefits. The president does not want a repeat performance of the political lashing he took from Democrats over Social Security and thus is not likely to take the lead, officials said.

"But this is not something that is going to go away if it is ignored," said one administration official. "Recognizing that, there has been a realization for months that we have to come up with alternatives."

Publicly, the administration has been looking to the commission for answers. But key members of the panel, including Senate Finance Committee Chairman Robert J. Dole (R-Kan.) and commission chairman Alan Greenspan, have insisted that the group cannot make final bipartisan recommendations without the involvement of Reagan and House Speaker Thomas P. (Tip) O'Neill Jr. (D-Mass.).

Sen. John Heinz (R-Pa.), a member of the commission, said yesterday, "There are broad and high-level discussions going on in an effort to discover if the president and O'Neill can productively meet."

Neither O'Neill nor Reagan has foreclosed the possibility of such a meeting, but their spokesmen contend that none is being planned.

The 15-member commission had set a Friday deadline to issue its final report. Yesterday the president stood fast against demands that he step directly into the politically explosive debate before the commission reports.

"We are not scared to touch the issue," Reagan said during a 16-minute meeting with reporters in the White House press briefing room. He had been asked to comment on Dole's contention last weekend that the administration is "frightened to death" about handling the financially troubled Social Security system.

Reagan said he wanted the commission, including "experts in the field of actuarial statistics and insurance and pension plans," to come forward with their own plan or alternatives for shoring up Social Security. Once that is done, he added, "then we will have alternatives."

But Heinz said yesterday, "It is a presidentially created commission -- the initiative was the president's." He added that Republicans "would like to see some leadership from the White House -- we hope it won't be over the edge of a cliff as it was two years ago."

Reagan took note of the uproar that greeted his last Social Security proposals.

"... Our previous experience had been that all we could succeed in doing was making it a political football and terrorizing the senior citizens and I don't think that we participated in making it a political football, but that seemed to be what was happening."