Rep. G. William Whitehurst, dean of Virginia's Republican House delegation, said today he will not seek a 10th term in Congress, setting off a scramble among several state legislators and others for his seat.

Whitehurst, 59, who has represented the Norfolk-Virginia Beach area since 1968, said he will return to Old Dominion University as a special lecturer in the spring of 1987 when his current term ends. He told reporters he decided to leave Congress because of an "accumulation of pressure" and a recommendation from his doctor that he should take a lighter work schedule.

His announcement, which has been expected, opens the door to what some politicans say will be a hard-fought contest between several well-known Democrats and Republicans in the 2nd Congressional District.

Republican state Sen. A. Joe Canada Jr., of Virginia Beach, considered the leading GOP candidate, said today that he is "very interested" and will make a formal announcement later.

Democratic Del. Owen B. Pickett, also from Virginia Beach, long has been considered a probable congressional candidate. "I am looking at it, but I have not made any decision," he said.

Pickett, a lawyer who is seen as a moderate conservative, encountered opposition from blacks in 1982 when he appeared to have the party's nomination for the Senate locked up. Some Democrats say his strength would be that he could dilute the strong Republican vote in Virginia Beach while drawing support from heavily Democratic Norfolk.

Democratic House Majority Leader Thomas W. Moss Jr. of Norfolk also is considering the Whitehurst seat.

Pickett and Moss are friends, and their friends said it is unlikely that they will compete against each other.

"Owen and Tom will work it out. I can't imagine them running against each other," said one Moss associate.

Other potential Democratic candidates include former Norfolk delegate Edythe C. Harrison, who lost a bid for the Senate last year to Republican Sen. John W. Warner, and Norfolk Mayor Joseph A. Leafe, a former legislator.

Although Whitehurst has never been considered a power on the Hill, his penchant for strong constituent service, support of the military, and a relatively low profile on many major Republican issues have left him unopposed since 1976.

"What caused me to leave at this time was an accumulation of pressure, tension," Whitehurst said at a press conference today on the ODU campus in Norfolk.

"You reach a point where you say, 'Enough is enough.' Some of them special interest groups can be very difficult, can squeeze you, make demands of you and some of them do it in a way that is not very attractive."

Whitehurst, who was a dean at ODU and television commentator when he won what had been a solidly Democratic seat in 1968, is the second-ranking Republican on the Armed Services Committee and a member of the House ethics committee. He will return to the university as the first recipient of the George and Linda Kaufman University Lectureship in Public Affairs, teaching courses in history, government and public affairs, according to a ODU spokesman.

"It is a big bridge to burn and yet I do so without any regrets," Whitehurst said today.

He said in a recent interview, "Let's face it . . . in a body of 435, you're easily immersed," but added it was "very important to me to believe there is a life after Congress. And there is."