Senate Minority Leader Howard H. Baker Jr. (R-Tenn.), insisting that he is "not going to be pushed off that rock" yet, said today he will announce his position on the Panama Canal treaties just before or at the start of Senate debate on the issue, probably in January or February.

Baker, under increasing pressure from within his party to take a stand, said qualifications or amendments to the treaties may be made before a final vote. He said he will not "abdicate" his leadership responsibilities by influencing the issue in the Senate before it comes to debate.

Baker said those qualifications could include changes discussed by Panamanian leader Omar Torrijos with seven senators who visited the Canal Zone last weekend. But Baker added he has no plans to visit Panama.

Talking with rereporters at the Southern Republican Conference at Walt Disney World here, Baker said preessure from the right wing has been steadily increasing, but he is still undecided.

He said he has received 22,000 letters on the subject, including 500 in support of the treaties. Tennessee newspapers have carried full-page advertisements imploring a "no" vote, he said, and at a football game he attended in Knoxville recently, an airplane passed over 84,000 fans trailing a banner that read, "No to Panama, write Baker." It was paid for by the American Conservative Union.

But both Baker, whose presidential aspirations have seemed threatened by the issue, and Republican national chairman Bill Brock said they believe the treaties will not be an issue in 1980.