(Updates to close) July 11 (Reuters) - Australian shares ended...

(Updates to close)

July 11 (Reuters) - Australian shares ended marginally higher on Tuesday ahead of Federal Reserve Chair Janet Yellen's congressional testimony later this week which investors will glean for clues on when the central bank will again tighten U.S. monetary policy.

The S&P/ASX 200 index (xjo) finished 4.46 points, or 0.1 percent, higher at 5,728.9 in a thin trading environment before Yellen's semi-annual monetary policy testimony before Congress on Wednesday and Thursday.

"Most people have positioned their portfolios ahead of this (Yellen's testimony) and very few people are prepared to react if she does really go into little more depth about her own personal views on financial conditions," said Chris Weston, an institutional dealer with IG Markets.

"Her views at the moment are well known to the market and it shouldn't be too surprised by what she's saying now."

Miners benefited from a sustained rally in iron ore prices, as the most-traded iron ore on the Dalian Commodity Exchange DCIOcv1 rose for a third straight day. [IRONORE/]

Major miners BHP (BHP) and Fortescue Metals Group (FMG) were up 1.1 percent and 3.5 percent, respectively.

Rio Tinto shares (RIO) gained 0.8 percent. A slight rise in oil prices fuelled further share-price gains for stocks of Aussie oil and gas majors, with sector bellwether Woodside Petroleum (WPL) up about 0.2 percent and fuel supplier Caltex Australia (CTX) nearly 0.8 percent higher.

New Zealand's benchmark S&P/NZX 50 index (nz50) finished up 0.6 percent, or 44.62 points, at 7,628.57.

Consumer staples and financial stocks pushed the benchmark up, with dairy products maker a2 Milk (ATM) posting the biggest gains by weight, up 5 percent.