Tip O'Neill is not only US legislator in China this week

Springtime during a nonelection year in Washington means cherry blossoms, the first shoots of green leaves, and congressional delegations spreading over the globe.

House Speaker Thomas P. O'Neill Jr. has been smiling under his Irish hat for cameras at China's Great Wall during his well-publicized trip to Peking. The Massachusetts Democrat is leading a bipartisan delegation of 14 other representatives on the goodwill tour.

But if those congressional ambassadors are not enough, there are plenty of others visiting China during the Easter break. Rep. John D. Dingell (D) of Michigan is taking nine members of the Energy and Commerce Committee, which he chairs, to Japan, China, and Hong Kong.

The Dingell group was scheduled to tour a Japanese auto assembly plant and talk to Chinese officials, according to a statement, which listed no plans for two days in Hong Kong.

Meanwhile, Rep. Jerry M. Patterson (D) of California is leading another Chinese trek, taking along three members of his banking subcommittee on international development institutions and finance. And Sen. Frank H. Murkowski (R) of Alaska is also in China, leading a group of Alaska businessmen who are seeking trade ties.

Not all of the lawmakers will be going to the Far East, however. Rep. Patricia Schroeder (D) of Colorado is leading a nine-member delegation to the southern flank of NATO for the House Armed Services Committee. Stops include Lisbon, Naples, Ankara, Beirut, Crete, and Athens.

Such travels have long been the subject of controversy on Capitol Hill, where defenders argue that members of Congress need a firsthand view of other countries and detractors say the trips often amount to boondoggles.

''Why do we have to be defensive about travel?'' says a staff member for the House Ways and Means Committee, adding that during his only trip he worked so hard that he would have ''paid'' to go home. ''Why should a group that has complete jurisdiction over trade with Japan be spited for taking a trip?'' he adds, referring to a Ways and Means delegation now in Japan.

But others see the trips as wasting taxpayers' money. A veteran congressional aide says the trips often are not necessary and members sign up for fun. The former House aide recalls that one of his congressional bosses had criticized junkets before being elected but then started taking the trips, even taking a family member to China.

Rep. Ron Paul (R) of Texas, arch opponent of foreign travel at government expense, has reintroduced his bill to ban all trips unless approved by a three-fourths vote of Congress. But such a measure is no more than a gesture in a Congress where 200 to 300 members take trips annually.

It is almost impossible to discover exactly how much is spent on congressional travel abroad each year. Congressional Quarterly (CQ), a weekly publication and news service, estimated $4.46 million for 1979, but it has since discontinued its survey because of the cost of gathering the information. No central accounting office keeps statistics, and trips are paid for by a variety of federal departments, Congress, and outside groups.

CQ's surveys have found that travel usually dips during election years, when members must spend time at home. Moreover, foreign travel can sometimes become a political liability. In 1980, a New York Democrat, Lester L. Wolff, lost his House seat after a Republican challenger ran TV ads about Wolff's travels to exotic places.