UPDATE 1-Komatsu Q1 profit surges on emerging market demand

* Q1 operating profit 54 bln yen vs yr-ago 8.3 bln yen

* Keeps recently revised FY forecast at 179 bln yen

* Shares up 1.6 pct before results, in line with sector (Adds background)

TOKYO, July 28 (Reuters) - Komatsu Ltd (6301.T), the world's No.2 construction machinery maker after Caterpillar Inc (CAT.N), posted a more than sixfold jump in quarterly profit on strong emerging market demand and kept its recently upgraded full-year outlook.

Komatsu and Caterpillar have been cashing in on steadily improving demand for excavators and other earth-moving equipment, helped by spending on housing and infrastructure projects in Asia and Latin America.

Last week, U.S.-based Caterpillar beat quarterly profit forecasts and lifted its annual outlook, while Japanese rival Hitachi Construction Machinery Co (6305.T) on Tuesday posted a return to profit. [ID:nLDE66L1LA]

Komatsu said April-June operating profit rose to 54 billion yen ($614 million) from 8.3 billion yen a year earlier. Quarterly revenue jumped 39.5 percent 447 billion yen.

The Tokyo-based company reiterated its forecast for operating profit to nearly triple to 179 billion yen in the year to March 2011. It had raised its estimate two weeks ago, citing strong sales in emerging markets. [ID:nN22131006]

Ahead of the results, shares of Komatsu rose 1.6 percent to 1,814 yen, in line with Tokyo's machinery sector subindex .IMCHN.T. The stock has lost 6 percent so far this year, underperforming a 4 percent fall in the subindex. (Reporting by Nobuhiro Kubo; Editing by Ian Geoghegan)