(Updates to close) Dec 14 (Reuters) - Australian shares ended...

(Updates to close)

Dec 14 (Reuters) - Australian shares ended at a more than four-month high on Wednesday, underpinned by mergers and acquisitions activity while traders awaited the outcome of the U.S. Federal Reserve's rate-setting meeting later in the global day.

The S&P/ASX 200 index (xjo) ended up 0.71 percent, or 39.55 points higher, to finish the session at 5,584.6. The index rose as much as 0.9 percent during the session and ended at its best level since Aug. 1.

Shares of lottery operator Tatts Group (TTS) rocketed to near 10-year highs after a Macquarie Group (MQG) led consortium launched a counterbid for Tatts, disrupting the agreed merger between Tatts and Australia's biggest bookmaker, Tabcorp Holdings Ltd (TAH)

Meanwhile, APN Outdoor Group (APO) rose to a four-month high after it revealed plans to buy out rival oOh!Media Ltd (OML)

On the downside, energy and basic material stocks suffered after oil prices fell on the back of a reported rise in U.S. crude inventories, and on concerns surrounding a planned output cut. [O/R]

Oil and gas company Santos Ltd (STO) ended down 2.9 percent while Oil Search Ltd (OSH) lost 2.08 percent. Among large cap miners, shares of BHP Billiton Ltd (BHP) closed 1.2 percent lower and Rio Tinto Ltd (RIO) lost 0.5 percent.

New Zealand's benchmark S&P/NZX 50 index (nz50) ended down 0.76 percent, or 52.35 points, to finish the session at 6,797.86, its lowest closing level in a month.

Entertainment firm SKY Network Television (SKT), which slashed its full-year guidance, was the biggest loser on the index, ending 10.8 percent lower.

Shares of power generation company Meridian Energy Ltd (MEL) ended down 1.9 percent after reporting poor retail sales volume for November.