UPDATE 1-GN Store Nord says no TPSA ruling before Sept

* Hearing aid maker postpones expectations for court ruling

* GN says sees no ruling in TPSA case before September

* GN's DTPG has claimed more than 5 bln DKK from Polish TPSA (Adds details)

COPENHAGEN, July 26 (Reuters) - Danish hearing aid and headset maker GN Store Nord (GN.CO) said on Monday a ruling by arbitrators in a case against Polish telecom TPSA, involving nearly a billion dollars, would not come before September.

In its annual report in February, GN said it had expected a decision from the arbitrators in 2009 but it did not give a new date for when the decision could come.

Shares in GN immediately fell as much as 3.8 percent, underperforming a flat Danish market on Monday.

The case has lasted nine years, and GN is involved through its 75 percent stake in the Danish firm DPTG of which Danish telecom TDC (TDC.CO) owns the remaining 25 percent.

The dispute is between DPTG on one side and Polish telecom Telekomunikacja Polska S.A. (TPSA) TPSA.WA -- controlled by France Telecom (FTE.PA) -- on the other.

It concerns determination of traffic volumes carried over the NSL fibre optical telecom network in Poland. DPTG says it is entitled to 14.8 percent of net profits from NSL during the period from 1994 to 2009.

DTPG has claimed around 5 billion crowns ($866 million) for 1994-2004, and, if the company wins in Vienna, it will submit further claims based on the same methodology for the remaining contract period from mid-2004 to 2009, GN said.

GN also said on Monday that it will inform the market immediately after a decision from the arbitration tribunal. (By Teis Jensen; Editing by Louise Heavens)