* Says court froze assets of TPSA's Dutch unit
* Dutch proceedings a new episode in long-running legal row
* GN Store Nord shares up 3 percent, TPSA up 0.6 percent
(Adds TPSA spokesman declining to comment; updates shares)
COPENHAGEN, Nov 24 (Reuters) - GN Store Nord has asked a Dutch court to enforce a ruling against Polish telecoms group TPSA, in a bid to collect 2.9 billion Danish crowns ($521 million) awarded to its DPTG unit.
Danish hearing aid and headset maker GN Store Nord said on Wednesday its DPTG unit had won a "prejudgment attachment" which effectively froze the assets of TPSA Finance BV, TPSA's Dutch unit.
The Dutch proceedings are a new episode in a nine-year legal dispute between GN Store Nord and TPSA, controlled by France Telecom, over income from a fibre-optic network built in Poland by DPTG.
"We are looking into the matter and do not comment at this stage," TPSA spokesman Wojciech Jabczynski said on Wednesday.
GN Store Nord said the Dutch proceedings were one of several steps its DPTG unit would take to collect the 2.9 billion crowns awarded to it in September by arbitrators.
The award covered income from the fibre-optic network from 1994 to mid-2004. GN Store Nord said its share of that award was about 2.1 billion crowns. GN has said it will file a second claim for more than 1 billion crowns against TPSA, covering the period from mid-2004 to 2009.
The company, which had said previously it would pursue enforcement proceedings in a Polish court, said TPSA had still not paid the money owed to DPTG under the Vienna arbitration tribunal's award.
Although GN Store Nord has not received any money from TPSA, it booked a one-off gain of 2.1 billion crowns in its third-quarter accounts from the lawsuit.
In October, TPSA reported a third-quarter loss, hit by provisions for GN Store Nord's claims, though TPSA has also called the award "disproportionate" and said it would use all possible legal means to reduce it.
GN Store Nord shares were up 3 percent and TPSA shares were up 0.6 percent at 1157 GMT. (Reporting by John Acher; additional reporting by Pawel Bernat in Warsaw; Editing by Dan Lalor and Erica Billingham) ($1 = 5.566 Danish crowns)