Gov. Harry Hughes' proposed new labor department, which appeared headed for speedy approval by the State Senate, hit an unexpected roadblock in the form of a filibuster led by a group of rural and Republican senators that was continuing early today.

The filibuster, the first of the session, was expected to last most or all of the night. Soon after it began at 5:10 p.m. Wednesday, senators began filing out of the chamber to relax in the lounge, leaving nearly every red leather chair vacant as Sen. Walter Baker (D-Cecil) launched into his speech.

Baker and others acknowledged, however, that they did not necessarily expect to derail the new department by the filibuster but intended to tie up the Senate in order to create a backlog of several other bills they did not like.

"There are several other bills we care about and this speech is slowing the process down," said Baker. He mentioned a measure being sent from the House that would make it easier for public schoolteachers to strike and another labor-backed administration bill that would generally guarantee union wages for state-funded work.

Senate leaders said they expected that both these bills, and probably one or two others, were headed for Senate filibusters during the remaining 12 days of this year's General Assembly.

Senate President Melvin A. Steinberg, in keeping with Senate tradition, did not attempt to cut off debate for several hours. Finally, at 9:45 p.m., the first such attempt failed when a motion to invoke cloture got only 16 votes; it needed the votes of 32 of the Senate's 47 members. A second cloture motion at 12:35 this morning got 19 votes.

"If necessary we will go until we collapse and then will get a few hours' sleep and come back," Steinberg said.

Before the filibuster began, Baker was busy organizing a desk full of books, letters and magazine clippings related to labor or new departments that he planned to read aloud to pass the hours. "I expect we can go all night. We've lined up 11 people to speak one-half hour each and then we'll start all over again," he said.

Despite the filibuster, the Hughes proposal to set up a new Department of Employment and Training--or labor department as it has become known--is likely to succeed. A preliminary vote on the issue this week showed 31 senators in favor of the department and only 10 against.

Hughes has lobbied hard to overcome initial legislative opposition to the department, which would consolidate several work programs and some 1,500 jobs from other state agencies. His staff appeared confident that the filibuster would not affect support for the proposal.

The primary objection of some legislators to the labor department has been that it would be an unnecessary and potentially costly addition to the state bureaucracy.

"My primary objection is that organizationally we don't need it," said Minority Leader John A. Cade (R-Anne Arundel). "We're spending money to do something we don't need to at a time when money is dear.