UPDATE 1-Omega Pharma sells Arseus stake

* Omega Pharma sells 24.04 pct stake in Arseus to Waterland

* Waterland to become Arseus' new reference shareholder

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BRUSSELS, Nov 9 (Reuters ) - Belgium's Arseus NV (RCUS.BR) said Belgian health products distrubutor Omega Pharma (OMEP.BR) agreed to sell its stake in the firm to private equity group Waterland, making Waterland Arseus' new main shareholder.

Omega Pharma would sell its remaining 24.04 percent stake, or 7.5 million shares in Arseus, a medical equipment and services company, to Waterland at 8.0 euros per share, Arseus said in a statement on Monday.

That price could be revised upwards by as much as another 2.75 euros per share when Waterland exits the stock, Arseus said, depending on the future performance of Arseus shares.

In addition, Waterland would acquire 330,000 shares, or a 1.06 percent stake, from Couckinvest NV, Arseus' second-biggest shareholder.

Arseus, whose products include dentists' chairs, surgical instruments and pharmaceutical ingredients, was previously a subsidiary of Omega Pharma and listed on Euronext Brussels and Amsterdam in October 2007 after an initial public offering.

Waterland would become Arseus' reference shareholder with a holding of 25.10 percent, Arseus said, adding that it expected the deal to be completed by Nov. 25.

The deal would enable Omega Pharma to strengthen its balance sheet with cash revenue that could be invested in its over-the-counter (OTC) core business, Omega Pharma Chief Strategy Officer Sam Sabbe said in the statement. (Reporting by Antonia van de Velde; editing by Simon Jessop)