Hank Paulson, the US Treas­ury secretary, warned on Sunday that adding direct spending measures to the $150bn economic stimulus package agreed last week would be “a slippery slope” that could derail the deal, urging the Senate to approve it quickly.

His comments highlight Bush administration concerns that signs of dissatisfaction from top Senate Democrats with elements of the deal – reached between the White House and House of Representatives – could at least delay the package.