* Sharjah court was to consider Dana's effort to invalidate sukuk
* But court may not issue ruling, case could drag on many months
* Dubai's Union Properties surges on IPO plan for unit
* Dubai-listed Khaleeji bank plunges as Bahrain shares fall
* Saudi's Najran Cement falls as it halts production line
By Andrew Torchia
DUBAI, Dec 25 (Reuters) - Gulf stock markets were mostly quiet in moderate trading volumes on Monday as Abu Dhabi-listed Dana Gas jumped ahead of a court hearing on its effort to avoid redeeming $700 million of Islamic bonds.
Abu Dhabi's index edged up 0.3 percent as Dana jumped 13.2 percent; it was the market's most heavily traded stock by far.
A court in the emirate of Sharjah was expected later on Monday to hear a case in which Dana is seeking to have its sukuk declared invalid under United Arab Emirates law.
However, the Sharjah court will not necessarily issue any ruling and the hearing could be adjourned. Legal actions related to the sukuk in both Sharjah and Britain may continue for months, even years, before the case is resolved, people familiar with the case have said.
Dubai's index edged up 0.2 percent as Union Properties, the most heavily traded stock, climbed 3.3 percent after saying it planned to list its ServeU facilities management unit in Dubai in the second half of 2018.
Bahrain's Al Salam Bank, the second most heavily traded stock in Dubai, jumped 7.7 percent to 1.12 dirhams after a 6.1 percent gain on Sunday, when a disclosure on the Bahrain exchange showed a key person involved with the bank had bought 250,000 shares.
In Bahrain, the bank's shares surged 8.5 percent to 0.115 dinar, equivalent to 1.12 dirhams.
Khaleeji Commercial Bank, another Bahraini bank which has soared in big trading volumes since it listed in Dubai last Tuesday, plunged 9.9 percent to 1.36 dirhams. Its shares in Bahrain sank 5.8 percent to 0.113 dinar, equivalent to 1.10 dirhams.
Saudi Arabia's index slipped 0.5 percent as Najran Cement dropped 2.2 percent after its board decided to halt its third production line, which has a daily capacity of 6,500 tonnes, and restart its second line, with a capacity of 3,000 tonnes, because of high inventories of clinker.
Saudi cement shares have risen sharply in recent weeks partly because of hopes for a pick-up in the cement industry as the government eases fiscal austerity. But Najran's decision suggested improvement in the industry might not come quickly.
Jadwa REIT jumped 4.3 percent after the real estate investment trust said it had bought two properties worth 148 million riyals ($39.5 million) in Mecca which would initially yield between 6.4 and 6.5 percent annually.
But utility Saudi Electric dropped 4.9 percent. It has been weak since mid-December, when it said it would pay the government any profits from the increase in electricity tariffs due to take effect in January.
In Qatar, the index fell 0.4 percent but Qatar First Bank, the most heavily traded stock, surged 6.7 percent, continuing a rebound from record lows that began in late November.
In Egypt, the blue-chip index rose 0.4 percent. Sharkia National Co for Food Security surged 10 percent after it said it had appointed Adel Abdel Halim al-Banna as acting chief financial officer. But Suez Bag plunged 10 percent to 34.85 pounds after Tora Cement said it had sold its 4.52 percent stake in Suez Bag for 26.01 pounds per share.
* The index fell 0.5 percent to 7,146 points.
* The index rose 0.2 percent to 3,355 points.
* The index gained 0.3 percent to 4,338 points.
* The index dropped 0.4 percent to 8,570 points.
* The index rose 0.4 percent to 14,843 points.
* The index edged up 0.03 percent to 6,345 points.
* The index gained 0.6 percent to 1,293 points.
* The index fell 0.6 percent to 5,023 points. (Editing by Gareth Jones)