Expansion of the airport and its runway would require investment of 98 million pounds ($164.6 million), Aena's Jose Manuel Vargas told Spain's Chamber of Commerce at an awards ceremony in London, according to a statement from the company in Madrid.

"The contracting of the work will begin as soon as the necessary permits are acquired, after a long and complex process that we hope will come to a positive conclusion in the coming weeks," he said.

Spain-based Aena, whose airports division is a potential privatisation candidate, bought Luton airport last year. It has stakes in more than 20 airports beyond Spain and 46 at home.

Luton is London's fourth-biggest airport with 9.7 million passengers in 2013 and capacity for up to 12 million. Vargas said it hopes to boost that number to 18 million.

The investment would have a positive economic impact by creating jobs, Vargas said, adding that shopping services at the airport would also be expanded, along with transport links to the City of London financial district.

One of the biggest beneficiaries of the expansion would be budget airline Easyjet, which recently secured more space at Luton.

Permission for expansion of London's biggest airports Heathrow and Gatwick is a political hot potato because adding capacity in those densely populated areas around the British capital is unpopular with voters.

A decision on the expansion of Gatwick and Heathrow has been pushed back repeatedly. ($1 = 0.5953 British Pounds)

(Reporting By Elisabeth O'Leary; Editing by Fiona Ortiz and David Goodman)