David Wayte has gone further than most of his West Coast contemporaries in opposing draft registration.

He demonstrated in front of a Santa Cruz post office. He sent the president a letter saying he was defying the law. He dropped out of college to devote more time to the organizing effort.

But as one of California's more than 100,000 nonregistrants, he has helped create a sociological--and perhaps political--phenomenon that has Selective Service officials here scrambling. As of last Oct. 1, only 51.2 percent of 18-year-old males in the nation's most populous state had registered for the draft--far below a 77 percent national average and lower than any other state or the District of Columbia.

"We maybe are a bunch of free, liberal thinkers here in California," said Keith Lamb, head of the state Selective Service program, after the figures, based on census and registration data, came out.

"I think California has a tradition of dissent," said Wayte, who faces a penalty of up to five years in jail and a $10,000 fine.

Of 7.1 million 18- to 21-year-old Americans required to register, 925,000 had not done so as of last month, according to the Selective Service. But the abundance of no-shows here so stunned California officials that last month Gov. Edmund G. (Jerry) Brown Jr. issued a statewide warning of the criminal penalties involved and Selective Service officials launched an energetic publicity campaign.

A spot check at 20 Los Angeles post offices showed average registration climbing from 54 to 150 a day per post office after the publicity campaign began, but the state's registration rate is still expected to lag behind the nation's, and California officials are struggling to explain why.

Coming a close second to California in the percentage of nonregistrants was the District of Columbia, where only 53.9 percent of 18-year-olds had registered as of Oct. 1. By comparison, the percentage of 18-year-old draft registrants last year in Maryland was 88.9 percent. In Virginia it was 77.1 percent.

Bill Smith, a Los Angeles attorney who cochairs the Committee Against Registration and the Draft, attributes the District's low rate of registration to its large black community, where "draft resistance is very strong."

California's low percentage of registrants, he said, may stem from not only the long history of opposition to the Vietnam war here but also an unusually well-organized draft resistance campaign in the state's major cities over the past two years, which managed to air public service announcements on rock radio stations telling teen-agers how to get draft registration counseling.

Joaquin Matias, an 18-year-old California high school senior, said many of his fellow seniors had ignored the public appeals to register. "They joke around and say they will fly to Canada. A lot of them just don't take it seriously," he said.

Matias suggested a crucial factor might be the large number of single-parent households in a state with a high divorce rate. Many of his classmates are left on their own by single working parents, while in the Midwest, where Matias spent last summer, "the families are a lot closer and parents make sure their sons register," he said.

Matias' own parents are separated, and he lives with a friend in a rented duplex. But he did register during a grace period a month ago after missing the initial deadline.

"Maybe lack of parental guidance does impact on it," said Col. John Abrahamson, western regional manager for Selective Service. But he said the major problem had been not "a lack of a sense of purpose or responsibility, but that large urban areas are hard to penetrate media-wise."

Selective Service's publicity blitz last month, including Spanish-language broadcasts in California's huge Latino community, have done much to close the gap, Abrahamson said, although new figures will not be available until at least April.

Even among older registration-age men like Wayte who have had a long time to get to the post office, California lags behind the national rate--84 percent of those born in 1960 compared with 91.6 percent nationwide, 82 percent for those born in 1961 compared with 94.5 percent nationwide and 72.1 percent for those born in 1962 compared with 88.5 percent nationwide.

"I refuse to take the first step in cooperating with my country's preparation for war," said Wayte, who plunged into the resistance movement shortly after President Carter announced the registration program in mid-1980.

After taking a prominent role at a San Francisco press conference and a Santa Cruz demonstration, Wayte received a letter from Selective Service last June saying his name would be turned over to the Justice Department if he did not register within 15 days. The U.S. attorney in Los Angeles sent him a similar letter in October.

Justice Department spokesman John Russell said 150 letters had been sent to people like Wayte who made public announcements or wrote letters to the government identifying themselves as registration resisters.

But the Justice Department will need President Reagan's direct authorization, which has not yet come, to find out the names of the thousands of other nonregistrants through Social Security records. Smith said he had heard of a case in which the Selective Service sent a letter to one man who had written to say his birthday was coming up and he was not going to register, only to discover "the birthday was his 95th."