* Most issues turn higher but 30-year bond dips
* Yellen reaffirms dovish policy leanings
* 10-year notes auction comes 2.612 percent high yield
(Adds late prices, auction results and comments)
NEW YORK, May 7 (Reuters) - U.S. Treasuries gained on Wednesday after America's top central banker said the world's largest economy remained on the mend but still required substantial monetary accommodation from Washington policymakers.
Federal Reserve Chair Janet Yellen told a congressional committee that, while America's labor markets had shown "appreciable" improvements, the U.S. expansion faced hurdles in a weak housing sector and from risks from geopolitical tensions.
Along with most other maturities, 10-year Treasury notes pivoted from early weakness on Wednesday and rose 3/32 in price to yield 2.588 percent in afternoon New York trading.
But yields on U.S. 30-year bonds, which on Friday touched their weakest level since last June 19 of 3.34 percent, rose on Wednesday to 3.395 percent after a decline in price for the day of 3/32.
"The message she is giving is that the labor market looks healthier, there are some concerns about housing, and there could be some increase in inflationary pressure in the next 12 months," said Jennifer Vail, head of fixed-income research with U.S. Bank Wealth Management in Portland, Oregon
Treasuries traders also kept a close eye on a sale of $24 billion of new 10-year notes by the Treasury Department that government officials reported had concluded with a high yield of 2.612 percent.
The auction was the second of three Treasury sales worth $69 billion scheduled for this week and came with the lowest comparable yield since June 2013.
Foreign central banks and other indirect buyers accounted for 49.28 percent of purchases, up from 44.67 percent in April.
"You have to say the auction went very well," said fixed-incomce strategist Anthony Valeri at LPL Financial in San Diego. "Even with drop in prices recently, there wasn't any hesitation to bid."
The auction's high yield was well within the 10-year's trading band as identified by Brian Rehling, chief fixed-income strategist at Wells Fargo Advisors in St Louis.
"We've been at a trading range for the 10-year of 2.80 and 2.57 for months now, and we are testing the lows," Rehling said. "I think rates will stay low. Inflation is low and rates in other developed countries are lower. It's hard to see ours going higher when you can get almost as much yield here on a 10-year than you can in Spain."
On Tuesday, prices of Treasuries were little affected by an auction of $29 billion of 3-year bills. The deal's high yield was 0.928 percent.
A $16 billion auction of 30-year bonds is due on Thursday.
(Additional reporting By Richard Leong in New York; Editing by Nick Zieminski and Cynthia Osterman)