The White House on Saturday defended Chief of Staff John Sununu against new allegations that he took personal and political trips at taxpayer expense and let corporate sponsors pay for his ski vacations.

As a result of the brouhaha over Sununu's trips, President Bush's legal staff prepared to tighten rules on his use of government aircraft.The policy review by White House counsel Boyden Gray will likely urge Bush to establish a process in which Sununu would have to get a sign-off on whether his trips are considered official, personal or political, a senior administration official said Saturday.

Currently Sununu makes the determination whether he or a political party should reimburse the government.

Gray's review will likely recommend that Sununu follow the same guidelines as Bush and Vice President Dan Quayle when they mix political travel with official business, said the official, who spoke on condition of anonymity.

In those cases, the Republican Party or a specific candidate's campaign fund must reimburse the government when Bush and Quayle and their aides travel on Air Force planes for political business.

Bush ordered Gray to look at the policy rather than investigate Sununu's travel, the senior official said. But if it becomes apparent that Sununu charged political trips to the government, reimbursements will be ordered, the source said.

Bush insisted Sununu had complied with the rules but hinted he might want them changed to avoid the appearance of impropriety.

Sununu came under renewed scrutiny in Time magazine and U.S. News & World Report issues published Saturday. They said his expenses on a ski vacation were paid by a lobbying organization and he attended Republican political functions while traveling at government expense.

White House spokesman Doug Davidson said, "The governor has complied with all the regulations, and the review is still underway." He refused further comment.

White House records last week showed Sununu took 77 trips on government aircraft, only four of them listed as personal.

Sununu's ski vacations, listed as official trips, cost the taxpayers $86,330, U.S. News said.

The magazine also said Sununu in May 1990 let taxpayers foot the bills for his attendance at two political gatherings with local party officials in Akron and Milwaukee after commencement appearances at Marquette University in Milwaukee and Akron University.

Both trips were classified as official, costing the government $19,582 to run the Gulfstream jet Sununu flew, said the magazine.

A Sununu aide, who spoke only on condition his name not be used, said, "We reviewed the billing for those trips and thought it was appropriate for the official designation to stand." We were in the cities for the purpose of attending commencement exercises."

But when Bush and Quayle make political stops, the Republican Party bears a proportionate share of the travel expenses under guidelines governing their travel.

A potentially more serious allegation against Sununu involves a December 1990 ski trip he and his wife Nancy took to Aspen, Colo.