* Profit likely up 11 pct to T$18.18 bln -12 analysts
* Apple's China revenue reached 20 pct in Q1 surge -analyst
* Hon Hai likely to book iPhone 6 revenue from Q2
By Michael Gold
TAIPEI, May 14 (Reuters) - Apple Inc assembler Hon Hai Precision Industry Co Ltd likely saw profit rise 11 percent in the first quarter when sales of Apple's iPhone overshot market estimates thanks primarily to Chinese demand.
The Taiwanese manufacturer, which reports earnings later on Wednesday, earns as much as 40 percent of revenue by building various versions of the iPhone, analysts say, and that figure could rise with increased distribution in China and a new model by year-end.
Shipments of iPhones beat market estimates by 15 percent in March, pushing Apple's January-March revenue to a record high for a post-holiday season quarter, when consumer goods sales typically fall.
Hon Hai usually books revenue from iPhone orders around two months before output reaches store shelves. So the iPhone surge likely helped Hon Hai book first-quarter net profit of T$18.18 billion, according to the mean estimate of 12 analysts polled by Thomson Reuters.
The Chinese proportion of Apple's first-quarter revenue likely reached 20 percent from 13 percent at the end of 2012, mainly due to increased marketing and cooperation with carrier China Mobile Ltd, said analyst Arthur Liao of Taipei-based Fubon Securities.
The iPhone's recent spread in China is a major reason why analysts expect Apple to sell as many as 100 million next-generation iPhones by the end of the year.
Sales could start as early as August, meaning Hon Hai - Apple's main supplier - is likely to book revenue from the iPhone 6 from the second quarter.
The new smartphone could push up Hon Hai's iPhone revenue from 31 percent in 2011 to 44 percent by the end of this year, and 46 percent in 2015, according to estimates from analyst Vincent Chen of Taipei-based Yuanta Securities.
"I don't think Hon Hai's other businesses and clients will be nearly as important as Apple, especially in the second half of the year," Chen said.
"The iPhone is huge, and if it slows down - either in sales or average selling price - that's going to have a major impact on Hon Hai."
In addition to the iPhone, the world's largest contract manufacturer also assembles laptops and tablets for Apple, as well as computers and servers for Hewlett-Packard Co and Cisco Systems Inc.
Shares of Hon Hai ended 0.3 percent higher ahead of the earnings report compared with a 0.7 percent gain in the broader TAIEX index. The stock has risen 9.7 percent since the start of the year versus the benchmark's 3.1 percent.
(Editing by Christopher Cushing)