The Philippines is having its first local elections since martial law was imposed nearly eight years ago and in most places voters can choose between candidates of President Ferinand Marcos' new political party, the New Society Movement, or Marcos' old political party, the Nationalist.

Marcos says the Nationalist really is not a party anymore. The choices are not that slim everywhere. In some provinces anti-Marcos candidates are putting up spirited campaigns and a few may inflict embarrassing losses on him.

But it is largely an election that Marcos has shaped, using his martial-law authority to keep opponents off balance by tailoring the election law and dipping lavishly into his governmental pork barrel. His foes are angry but largely resigned to another debacle. "There is no question," concedes an irate opposition leader, Lorenzo Tanada, Marcos' new party "will win in a landslide."

Marcos, 62, has exercised monarchical powers since he imposed martial law in 1972. The only election since then was a 1978 interim assembly election which Marcos' candidates ran off with amid protests of widespread fraud.

There have been no local elections since 1971 and most provincial governors, mayors and lesser officials have remained in office for nine years. Until a few weeks ago, 80 percent of local officers had been incumbents since 1971. Those who died were replaced by Marcos appointees.

Next Wednesday, voters will choose some 19,350 local officials. Many candidates are those whom Marcos has chosen to remain in office. A large number of contests are family feuds and factional fights. Few involve a direct challenge to Marcos' national sovernment.

It was almost an election to which nobody bothered to come. Neither the opposition Liberal Party nor Laban, an umbrella group of Marcos' foes, is fielding candidates -- a protest against martial-law and the president's restrictive election law.

That left Marcos' New Society Movement and the Nationalist Party, which had been his vehicle in rising to power 15 years ago and over which he still claims titular leadership.

On Jan 13, Marcos gave the Nationalists the green light to run candidates against his own New Society, observing that they could "bring out the support of the opposition."

But four days later, he declared he would challenge the election of any Nationalist candidate who won, insisting that the party had in fact been dismantled in 1978 when it chose to field joint candidates with Marcos' new party.

That was shocking news to the president's old cronies in the Nationalist Party, many of whom had helped elect him in 1965 and had stayed largely faithful every since. Marcos "has no right to dismantle the grand old NP which put him in power," declares a former House of Representatives speaker, Jose Laurel. The party's president, Jose J. Roy, asserts that the meeting Marcos says dismantled the party never took place.

The nationalists are running candidates in 60 out of the 79 provinces, Roy says, and many will win because they are familiar old names in their communities. But many of them are also friends of Marcos who happened to get caught on the wrong side of the ballot when the election suddenly was called in December.

Marcos' usual opposition is running about 1,000 candidates against him under an umbrella organization called the National Union for Liberation (Laban in Filipino). Hastily improvished, it is running several spirited campaigns in Manila and nearby provinces but it is hampered because it does not qualify for bloc-voting privileges, which permit a voter to write in one party name for several candidates. Each voter who supports National Union candidates must write in every candidate's name seperately.

The election's biggest surprise is its timing, which still puzzles observers here. Last September, Marcos hinted that there he would permit local elections in early 1981. But in December, he suddenly scheduled them for Jan. 30, giving opponents just about one month to prepare.

Opponents say he wanted to stage a quick election he could win handily and translate into a national mandate. Others think Marcos wanted an election before the flagging economy gets worse because of the next round of oil price increases.

The new law governing this election is tailored to protect Marcos from any rude shocks. It excludes from the voting the post of metro Manila governor, who happens to be his wife, Imelda. It limited bloc voting to accredited parties. It barred any candidate who had been accused of disloyalty or subversion, and that meant his chief rival, Benigno Aquino, who charges and who might have run from his cell for provincial governor of Tarlac.

The Supreme Court nullified that provision of the law Wednesday, but Aquino does not want to run anyway.

Marcos and his wife have put on a strenuous campaign for New Society Movement candidates. In a typical day on the hustings this week they went to Caloocan City and promised money to finance a new waterworks system and 100 new water pumps and hinted they would expropriate some landed estates for the benefit of qualified citizens.