UPDATE 1-Restaurant operator Alsea budgets higher Mexican labor costs

(Adds details from analysts' call)

MEXICO CITY, Oct 25 (Reuters) - The head of Mexico-based restaurant chain operator Alsea on Wednesday warned of higher Mexican labor costs next year, but said the firm would look to maintain profits without hiking its prices.

"We cannot compensate with prices," CEO Armando Torrado told analysts on a call, saying a proposal to cut Mexico's working week to 40 hours - which is being discussed by Mexico's Congress and could come into force by April - could push the company to negotiate better prices with raw material suppliers.

"We cannot lose any margins so we need to work in other areas," Torrado said, adding more disposable income for Mexicans nationwide could boost its restaurant sales. This comes as the finance ministry forecast some 3.5% GDP growth this year.

Alsea, which operates chain stores such as Starbucks , Burger King and Domino's Pizza across Europe and Latin America, posted a 56% jump in quarterly profits Tuesday driven by hungry customers in its home market, Mexico.

Torrado added that if the working week is reduced in line with that in other countries across Europe and South America, this would represent a "strong impact" of some 700 million pesos ($38 million), without specifying the time period for the hit.

Alsea, he said, is also cautiously budgeting for a minimum wage hike of around 20% from January, from a current level of 207.44 pesos ($11.33) per day in most parts of the country.

This would affect some 30% of Alsea's workforce, largely Domino's Pizza deliverers and waiters working at the Vips Mexican restaurant chain, Torrado said. ($1 = 18.3074 Mexican pesos) (Reporting by Sarah Morland and Aida Pelaez-Fernandez; Editing by Kylie Madry)