Gov. Michael S. Dukakis was greeted by cheering Massachusetts state employees yesterday when he returned to the governor's office for the first time since winning the Democratic presidential nomination. But a Republican complaint was likely to force him to wait for $46 million in federal campaign funds.

"This will probably add some time to the deliberative process," Sharon Snyder, a Federal Election Commission (FEC) spokeswoman said of a GOP request that federal money be held up until the FEC can rule on questions raised by Sen. Lloyd M. Bentsen's (D.-Tex.) pursuit of the vice-presidency and re-election to the Senate at the same time.

Vice President George Bush, like Dukakis, was off the campaign trail after winding up a trip Sunday night. Bush was polishing a speech in which he planned to call for tougher ethical standards for government officials and members of Congress.

As for Bentsen's races, Jann Olsten, executive director of the Republican Senate Campaign Committee, said yesterday, "There is no question that one is going to impact the other."

"A dollar spent by Senator Bentsen in Texas, whether for the Senate or the vice presidential campaign, is going to directly and immediately benefit both," said Olsten. "It just isn't fair."

An unusual Texas law permits Bentsen to run for vice president at the same time he is on the ballot for re-election to the Senate.

Bentsen's latest campaign report showed him with $3.9 million on hand for his Senate race against GOP challenger Beau Boulter.

While there is no lid on how much he can spend on his Senate campaign, federal law limits direct expenditures in the presidential campaign to the federal campaign funds--divided equally between the major party candidates.

Dukakis campaign spokesman Leslie Dach shrugged off the possible delay in receipt of the $46 million.

"Our campaign is moving full steam ahead with plenty of momentum from the convention," he said.

One sign of the kind of momentum cheering the Dukakis campaign was a new poll taken in Texas by Peter Hart Research Associates.

The survey of 502 likely voters on Friday and Saturday, the two days immediately following the Democratic Convention, said Dukakis was favored by 50 percent and Bush by 40 percent. A pre-convention survey in Texas by Hart had the two candidates tied at 46 percent each.

Bush was spending the week in Washington, tending to official duties.

He will deliver a speech today at the Library of Congress on ethics in government, prescribing "high standards" to prevent conflict of interest by federal officials, including members of Congress. Aides say Bush wants a strengthened Office of Ethics in the White House.

The speech, long in the making, was delayed until the release of the report by independent counsel James M. McKay on Attorney General Edwin Meese, which said Meese probably broke two tax laws and twice violated a criminal conflict-of-interest statute. McKay sought no charges.

Bush says the Justice Department, in particular, must be above even the appearance of wrongdoing. "I would have to reluctantly conclude--reluctantly because I like Meese--that those standards were not met," Bush told reporters last Saturday.

When Dukakis appeared at the Massachusetts Statehouse yesterday morning shortly before 9 a.m., about 20 state employees greeted him with applause.

Once in his office, Dukakis took up where he left off before the convention and became immersed in efforts to defuse legislative protests over his use of a line-item veto to bring the state budget into balance.

Some legislators were calling for a special session to try to override some of his vetoes of $138 million in appropriations.

Meanwhile, at the White House, spokesman Marlin Fitzwater said that it is likely President Reagan will veto plant-closing legislation that Dukakis has been making an issue in the presidential campaign.