* Time for Obama to "speak out" on trade, senator says

* Absence of US trade agenda under Obama is "palpable"

* Obama acknowledges need for more robust approach

* Faster action urged on Korea, Colombia, Panama deals

(Adds more quotes, details)

By Doug Palmer

WASHINGTON, Nov 10 (Reuters) - As U.S. President Barack Obama heads to Asia this week, a top Democratic senator urged him to join trade talks with Vietnam, New Zealand and others as part of an emerging Pacific trading bloc.

Senate Finance Committee Chairman Max Baucus said on Tuesday he was concerned Obama was not moving aggressively enough to forge trade ties in a region that offered the brightest hope for U.S. exporters.

Since Obama took office ten months ago, "the United States has lacked a comprehensive trade agenda and that absence is palpable," Baucus said.