* OHL to spin off Mexico concessions unit-sources
* Sees share offer of $700 million to $800 million-sources
* Roadshow to start in late Oct
* Offering seen pricing in early November-sources
* C.Suisse, Santander, UBS and BBVA underwriters-sources
By Andres Gonzalez and Clare Baldwin
MADRID/NEW YORK, Oct 11 (Reuters) - Spanish builder Obrascon Huarte Lain is preparing to spin off its Mexican airport and road operating concessions unit and has hired banks for a November offering worth $700-800 million, said sources familiar with the plan.
The offering for OHL Concesiones Mexico is expected to price in early November after a roadshow kicks off at the end of October, the sources said.
According to OHL's website OHL Concesiones in Mexico was worth around 1.6 billion euros ($2.24 billion) as at April 30.
OHL declined to comment.
Credit Suisse and Spain's biggest bank, Santander, will act as joint global coordinators and UBS and BBVA will act as joint bookrunners, the sources said.
Spanish builders have turned to their international businesses for cash to pay down debts or fund fresh investments. Credit remains tight in Spain, with banks bearing the brunt of a debt-fuelled construction boom and bust.
Last week Spanish infrastructure giant Ferrovial agreed to sell a 10 percent stake in Canadian toll road 407-ETR for 894.3 million Canadian dollars.
Builders are also feeling the impact of austerity measures, including the cancelling of state-funded infrastructure contracts, as the government scrambles to reduce its public deficit and avoid a Greek-style debt crisis.
About 87 percent of OHL's core earnings were generated abroad in 2009 and the company's chairman, Juan Villar Mir has long said he would continue to seek international expansion, particularly in North America.
OHL is also currently considering the acquisition of 51 percent of Polish peer Hydrobudowa in order to expand its construction business in Eastern Europe. ($1=.7158 euros) (Additional reporting by Tracy Rucinski; Editing by Greg Mahlich)