Former Fairfax State Del. Wyatt Durrette kicked off his Republican campaign for state attorney general last night in Fairfax with the endorsement of Sen. Paul Laxalt (R-Nev.), one of President Reagan's closest advisers.

Speaking to a crowd of about 300 supporters at the Springfield Hilton, Laxalt said that a victory for Durrette as J. Marshall Coleman's successor "in a great sense is going to be read as a referendum on the Reagan administration."

Coleman is the Republican gubernatorial candidate.

Durette's endorsement by Laxalt, who managed Reagan's presidential campaign and is an intimate of the president, was seen as an indication that the Republican administration is willing to make Virginia a proving ground for its new economic proposals. Although Reagan has not committed himself to campaign appearances on behalf of statewide Republican candidates in Virginia, several of his aides have begun making the campaign rounds.

Appearing at the podium alongside his old GOP political foe Coleman as well as Sen. John Warner (R-Va.), Durrette pledged to reform the state's criminal justice system and crack down on the recent upsurge in crime.

He promised to reform the state's parole system, strengthen its grand jury system and grant more assistance to victims.

"The agenda for the 80s is to make criminals serve more of the time to which they have been sentenced," he said. "I don't like the fact that many Virginians feel they have to turn their homes into armed camps to protect themselves from crime."

Durrette, who will face no opposition for the nomination at the Republican convention in Virginia Beach next month, also stressed Reagan ties with a call to his supporters to back the Reagan administration's new turn toward federalism -- or the granting of greater power to state and local governments by the federal government.

"America will be watching Virginia in 1981 to see if Virginia remains true to the principles Washington has seen fit to announce," he said.

The appearance of Coleman and Durrette together seemed to halt, at least for the time being, speculation about what has been a long simmering dispute between the two men. Although Durrette went into the 1977 Republican state convention with a plurality of delegates pledged to his attorney general campaign, Coleman won the nomination and the election. Many in the party have been critical of him since, alleging that he shifted to the right to edge out Durrette in the convention balloting, and back to the left in the general election campaign.