UPDATE 1-Compal sees stronger Q3 shipments -analysts

* Q3 laptop shipments to climb 20 pct q/q - analysts

* Company declines comment; holds investor conference Friday

* Shares up 4 pct

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TAIPEI, Sept 3 (Reuters) - Taiwan's Compal Electronics (2324.TW), the world's No. 2 contract laptop PC maker, expects its third-quarter shipments to rise about 20 percent from the preceding three months, three analysts told Reuters on Thursday.

A key supplier to top PC brands such as Hewlett-Packard Co (HPQ.N), Acer Inc (2353.TW) and Dell Inc (DELL.O), Compal shipped 7.9 million units in the second quarter.

The analysts said they got the forecast from the company, but declined to be identified because Compal had not yet officially announced its outlook for the current quarter. It is due to hold its investor conference on Friday.

"The company gave us the forecast recently when we asked for it," said one of the analysts. "However, it is likely to give a range of about 15 to 20 percent during the conference so as to moderate expectations."

Compal's Chief Financial Officer Gary Lu declined to comment on the figure.

Compal competes with bigger rival Quanta Computer Inc (2382.TW) to make laptop PCs for the world's top tech brands, who typically do their own design work but outsource manufacturing so they do not have to manage labour-intensive production lines.

The third quarter is typically the busiest season for most PC firms, with demand rising as students return to school after summer holidays and production ramps up ahead of the peak holiday shopping season.

This year, PC shipments are expected to climb even further due to Microsoft Corp's (MSFT.O) launch of its next-generation Windows 7 operating system in October. Past launches have typically led to a spike in computer sales.

The analysts gave the forecast after the Taiwan stock exchange closed on Thursday. Compal shares were up 4 percent, beating a 0.9 percent advance on the benchmark TAIEX share index .TWII. (Reporting by Kelvin Soh and Roger Tung; Editing by David Holmes)