UPDATE 1-Ethiopian rebels arrested for dam raid

* Three rebels arrested, accused of dam attack

* Opposition says government version not trustworthy (adds opposition)

ADDIS ABABA, June 26 (Reuters) - Ethiopia said on Friday it arrested three Oromo Liberation Front rebels who beat up Chinese technicians in a raid on a dam construction site in the west.

State TV said three Chinese were in hospital after being badly beaten by the OLF gang during the attack this week at the Neshie Dam. The statement said they were planning "terrorist activities" there, and were later caught by security forces.

"The culprits beat Chinese technicians working at the site, robbed laptops, printers, digital surveying machines and other equipment at the site," it said.

The three were paraded on TV, together with guns, communications equipment and bomb-making materials.

Prime Minister Meles Zenawi's government blames the OLF, which has fought for autonomy for its southern homeland since 1993, for various explosions in the capital Addis Ababa.

Addis Ababa accuses arch-enemy Eritrea of training and funding the OLF and other small rebel groups in Ethiopia's remote, outlying areas. Asmara says that is an excuse to mask popular unrest with Meles' government.

An opposition figure said the government's version on the arrests was not credible.

"Unless there is ample evidence that the three persons apprehended as terrorists were attempting to carry out terrorist activities along the dam site, we cannot trust what the government is alleging," said Gebru Gebremariam, chief whip in parliament for United Ethiopian Democratic Forces (UEDF).

"The government always carries out massive arrests of the Oromo people under the pretext of terrorism." (Reporting by Tsegaye Tadesse, Writing by Andrew Cawthorne)