DUBAI, June 30 (Reuters) - Sharp rises in oil prices and global stock markets may push Gulf bourses up slightly on Thursday but with long Eid al-Fitr holidays looming next week, investors look unlikely to buy aggressively.

MSCI's broadest index of Asia-Pacific shares outside Japan is up 1.4 percent and Brent crude jumped more than 4 percent overnight to above $50 a barrel, though it has since come off its highs.

This could boost Saudi petrochemical stocks in particular. Nevertheless, tight ranges and modest trading volumes in the Gulf over the past couple of weeks suggest investors are not in the mood to stage an extended bull run.

Another sign of caution in Saudi Arabia came on Wednesday when shares in retailer L'azurde Company for Jewellery closed 7.6 percent higher at 39.80 riyals as they listed, off their intra-day high of 40.70 riyals. It is unusual for a Saudi stock not to end up its 10 percent daily limit on its first day of trade.

(Reporting by Andrew Torchia) ((andrew.torchia@thomsonreuters.com; +9715 6681 7277; Reuters Messaging: andrew.torchia.thomsonreuters.com@reuters.net))