Lobbyists for veterans' groups will have their hands full early next year trying to preserve one of the most valuable - and controversial - benefits left to short-term military veterans. It is the Veterans Preference Act, which entitles veterans to bonus points on Civil Service job test scores and extra insulation when there are layoffs in federal agencies.

President Carter and his Civil Service team came on strong against veterans' preference earlier this year. It was a pattern other Presidents have followed shortly after taking office - usually under pressure from women's groups. It also has been the practice to drop the idea of dropping veterans's preference after the White House had learned what a political bombshell it is.

Some obsverors thought the Carter team had learned the same political lesson. In recent weeks, there has been little mention of the "evils" of veterans' preference and, indeed, some kind words for it. But top administration officials say the war is only being postponed until next year. Then President Carter will present a package of civil service jobs "reforms" that will include some dilution of veteran's preference benefits.

Nobody expects the President to argue - he would lose in Congress anyhow - for abolition of all veterans' preference benefits. They do expect he might make a pitch for a "one-shot" use of some job benefits for veterans shortly after they leave service and join the job-hunting parade.

As the number of nonveteran males increases in the job market - thanks to the elimination of the draft - officials expect to get more support from nonveteran males (now about 50 per cent of the work force) as well as from women's groups.