* Austria wants to keep at least 25 pct of Telekom Austria
* Slim's taking a majority a "secondary question" - chairman
* Telekom Austria shares slip 0.9 pct, in line with sector
VIENNA, Jan 31 (Reuters) - Austria is open to Carlos Slim's America Movil taking a majority stake in Telekom Austria, the head of the state holding company said, paving the way for a long-awaited move by the billionaire investor.
Rudolf Kemler said it was a "secondary question" whether Slim, who is keen to reduce his dependence on the increasingly regulated Mexican market, bought a majority of Telekom Austria as long as the Austrian government kept at least 25 percent.
"For strategically important companies ... we don't want to go below a blocking minority," Kemler told Austrian ORF radio on Friday, referring to a 25 percent threshold that ensures the government's point of view is considered on major decisions.
"The question of Carlos Slim's overtaking us and whether it is by only two or three percentage points or whether he goes above 50 (percent) is actually a secondary question," said Kelmer, who is also chairman of Telekom Austria.
America Movil declined to comment.
Telekom Austria shares, which have been buoyed by takeover speculation as well as optimism for the sector, closed up 0.68 percent at 6.487 euros, slightly outperforming the Stoxx European telecoms sector index.
America Movil's stock was down 1.6 percent at 1744 GMT, double the decline posted by Mexico's IPC blue-chip share index .
Austria, through its OIAG holding company, is the biggest shareholder in the former state telecoms monopoly, with just over 28 percent. America Movil holds just under 27 percent.
Bankers and industry sources have told Reuters they expect America Movil to make a bid for majority control soon.
Slim, who bought an initial large stake in Telekom Austria in June 2012 along with a major stake in Dutch KPN, is keen to avoid a repetition of the problems he had in the Netherlands, where he was forced to retreat after a takeover offer seen as hostile was rebuffed.
America Movil Chief Executive Daniel Hajj said in an interview last year the Latin American telecoms group did not plan a hostile takeover of Telekom Austria, and both sides have described the relationship as cordial and constructive.
Acquiring a majority in Telekom Austria would allow Slim, who has no history of holding minority stakes, to consolidate the company's results in those of the America Movil group.
Although Telekom Austria's market value has fallen by about a third since America Movil first bought its stake, it has risen again by about 9 percent this year on hopes for more consolidation and better margins in European telecoms.
Telekom Austria is the biggest player in Austria, where it is in cut-throat competition with Deutsche Telekom's T-Mobile and Hutchison Whampoa's Drei.
All-inclusive monthly packages are still available for as little as 10 euros ($13.56) per month and are among the cheapest in Europe despite Drei's acquisition of rival Orange a year ago.
Telekom Austria Chief Executive Hannes Ametsreiter said on Thursday he did not rule out a return to the price wars of the past as he expected new players to emerge this year to take advantage of cheap capacity on Drei's network.
Telekom Austria also operates in seven southeastern European markets outside Austria including Bulgaria, Croatia and Belarus.