* German court reduces total fine on 5 companies
* Cuts fines to 330 million euros from 649 million euros
* Case dates back to 2003
* Shares in Holcim, Lafarge rise
(Adds details on Lafarge, other companies, comments)
FRANKFURT/ZURICH, June 29 (Reuters) - A German court has slashed the fines levied by antitrust authorities against five of the world's largest cement makers, citing difficulties in assessing the profits reaped from the collusion. The court in Duesseldorf nearly halved the total fines to 330 million euros ($462 million) from the 649 million euros initially imposed by the German Cartel Office in 2003 on companies including France's Lafarge, the world's largest cement maker, and Switzerland's Holcim, the second largest.
A court spokesman said the fines were cut because some assumptions made by the Cartel Office to calculate the surplus reaped by the companies could not be upheld.
HeidelbergCement, which was handed the biggest fine, said on Monday it now had to pay 170 million euros instead of 252 million initially.
Holcim said its fine was cut to 14.6 million euros from 74 million, adding it would now examine its legal options.
The court said Lafarge's fine was cut to 24 million euros, down from an original 86 million.
Peer Dyckerhoff said it had to pay 50 million euros, down from 95 million previously.
Privately held Schwenk's fine was roughly halved to 70 million euros.
Shares in Holcim had gained 3 percent by 1442 GMT. Lafarge was up 3.6 percent, while HeidelbergCement had fallen 1.9 percent. (Reporting by Matthias Inverardi, Jason Rhodes and Ludwig Burger, editing by Will Waterman) ($1=.7143 Euro)