Barack Obama will move swiftly to unpick many of what he sees as the most egregious acts of the Bush administration when he enters the White House in January, including restrictions on stem cell research and moves to allow oil drilling in wilderness areas, a leading member of his transition team said yesterday.

John Podesta, a former chief of staff to Bill Clinton whom Obama has put in joint charge of his transition process, indicated the incoming president would use extraordinary powers to force through rapid change. "There's a lot the president can do using his executive authority without waiting for congressional action, and I think we'll see the president do that," Podesta said.

Podesta singled out restrictions applied by George Bush, in 2001, on federal funding of stem cell research, as well as recent moves by the White House to dilute environmental protections against oil drilling, as two areas in which quick action may be taken. "You see the Bush administration, even today, moving aggressively to do things that are probably not in the interest of the country," he said.

Podesta's comments could be interpreted as a warning to the Bush administration not to forge ahead with controversial decisions in the weeks of transition, a ploy used by many outgoing presidents.

According to the Washington Post, a team of about 50 Obama advisers have worked for months identifying some 200 Bush policies that are possible targets. Other areas of action may include reproductive rights, food and drug regulation and immigration enforcement.

Podesta's signal that the new administration would act quickly to negate several key provisions left by the outgoing one came as the president and president-elect prepared to meet today. Bush will show Obama around the White House, followed by private talks likely to focus on national security, the wars in Iraq and Afghanistan and the economic crisis.

Since last Tuesday's election, Obama and his team have focused on the economy, which they have underlined as their number one priority. But by flagging up stem cells and drilling, the team has also indicated it means to move on several fronts, meeting the expectation of change unleashed by Obama's campaign. A volley of executive orders reversing key Bush policies would have the benefits of being relatively quick to implement, as they would not involve congressional approval, and of costing little money.

Stem cell research has been a rallying cause for American liberals since Bush blocked federal funding for all but a few sources of old cells in August 2001. Scientists have complained the restrictions, inspired by the Christian right, have held back US dynamism in a research field seen as a possible route to cures for conditions such as Alzheimer's.

Podesta pointed to attempts by the Bush administration in its dying days to expose tracts of public land in the west to oil and gas drilling. In recent weeks the US Bureau of Land Management has offered up about 360,000 acres in Utah to oil and gas companies, with auctions of the leases likely before Obama takes over. "They want to have oil and gas drilling in some of the most sensitive, fragile lands in Utah. I think that's a mistake," Podesta said.

The Sierra Club, the country's largest grassroots environmental organisation, said it was concerned about last-minute changes from the Bush administration. "They have consistently weakened protections over the last eight years, and we are encouraged that the Obama team plans to act to clean up the mess when they get into office," the club said.

Tony Blair, reacting to Obama's victory yesterday, said: "There is this huge weight of expectation, but it is at least possible to meet a reasonable part of those expectations."