Linde-Praxair merger deal falls behind schedule -source

* $65 bln merger of equals intended to create market leader

* Deal has run into unexpected resistance from German unions

* Linde says still working towards May 10 deadline (Adds details, background)

MUNICH, Germany, April 13 (Reuters) - Linde and Praxair's $65 billion merger talks are facing legal complexities that mean the agreement will not be finalised as planned before Linde's annual shareholder meeting on May 10, a source familiar with the situation said.

The all-share U.S.-German merger of equals is intended to create a market leader that will overtake France's Air Liquide and reunite a global Linde group split by World War One a century ago.

Adding to the complexities, the deal has met unexpectedly strong resistance from German trade unions who fear a dilution of their influence when the headquarters moves out of Germany and more profitable Praxair applies its operating practices worldwide.

A Linde spokesman said the two companies were still working towards finalising the business combination agreement before the AGM, but could not rule out that it would be later.

Linde is not planning to allow shareholders to vote on the deal at the AGM, arguing that each investor would in any case have to make an individual decision whether to tender his or her shares.

German private-investor association DSW has already demanded that an extraordinary shareholder meeting be called if the deal is not wrapped up before the AGM. (Reporting by Jens Hack; Writing by Georgina Prodhan; Editing by Christoph Steitz and Keith Weir)