A free trade pact with Peru is moving toward final approval in the US Congress, but separate trade deals with Colombia and Panama face big obstacles, a senior US senator said.

Senate Finance Committee Chairman Max Baucus, a Montana Democrat, said in remarks to a trade group he expected his committee to formally approve the Peru agreement, which would be the first of four remaining votes on the pact.

The House of Representatives Ways and Means Committee and the full House and Senate also must approve the agreement before it becomes law. That could happen this month.

House Democrats are expected to link approval of the Peru agreement to a major expansion of a federal assistance program to help workers who have lost their jobs because of trade.

Two other free trade agreements with Panama and Colombia face significant problems in Congress, Baucus said.

The decision of Panama's National Assembly to elect as its leader a man wanted in the 1992 killing of a US soldier is "a very serious issue," Baucus said.

At the very least, Panama needs to "give some comfort that they're sufficiently taking this incident seriously. And that's not been shown yet," he said.

Colombia has "come a long, long way" in reducing violence against labor leaders, but needs to do even more to win congressional approval of the free trade pact, Baucus said.

"Basically those include, not just arrests of persons accused of murdering labor leaders but some prosecutions. (They're) a little weak in prosecutions," Baucus said.

The senior Democrat said he supported the trade pact with Colombia, but could not give a timetable for action.

"There'll be a time when members of the Senate say 'OK, Colombia's done enough, so let's bring it up.' We're not there yet," Baucus said. (Reuters)