Amplats says AMCU union now represents 60 pct of miners

* AMCU dominant on platinum belt

* Figures show turf war rumbles on

* Separate wage deal puts pressure on AMCU

By Ed Stoddard

JOHANNESBURG, Dec 13 (Reuters) - Upstart South African miners' union AMCU has increased its membership at Anglo American Platinum , the world's top producer of the metal, by 50 percent in the last five months and now represents 60 percent of shaft workers, the company said on Friday.

The new figures, supplied to Reuters from the company's human resources department by spokeswoman Mpumi Sithole, come as the hardline Association of Mineworkers and Construction Union faces a fresh challenge to deliver after rival unions signed a wage deal this week with the company.

AMCU emerged as the dominant union in South Africa's platinum belt last year, after winning over tens of thousands of members from the National Union of Mineworkers in a vicious turf war that killed dozens of people and triggered a wave of wildcat strikes.

But the NUM has said it wants to recover its representation in the platinum shafts and having closed the pay deal at Amplats this week it leaves AMCU's rank and file without any increase at a time when their co-workers will be taking home more pay, back-dated to July and just in time for Christmas, without having had to sacrifice any income in strike action.

"If you have a union that gets an increase for its members, that's delivery. This will make members want to come back to us," NUM spokesman Lesiba Seshoka told Reuters. The deal does not extend to AMCU members.

The pay increases range from 7.5 to 8.5 percent, far short of the more than doubling in entry-level wages demanded by AMCU under the populist battle cry of a "living wage" that was first evoked decades ago by black South African miners.

AMCU activists based in the platinum town of Rustenburg said on Friday they were determined to hold out for more.

"We are pushing for the big increase," Patrick Chakane, an an AMCU member with Amplats, told Reuters by phone.

The union has permission from a government mediator to call strikes at Amplats, Impala Platinum (Other OTC: IMPUY - news) and Lonmin (LSE: LMI.L - news) , but is not expected to do so before the New Year.

A simultaneous stoppage at all three could bring over half of global platinum production to a halt.

PLATINUM BATTLE GROUND

Meanwhile NUM activists have taken to wearing T-shirts with slogans such as "Relax ... NUM is here to stay" as it lays the groundwork to try and win back support.

But the latest Amplats' figures underscore just how tough it will be to win back members although NUM sources have said its own estimates differ from the company's, which shows it only has 20 percent representation at Amplats.

And the NUM wage agreement could prove a flashpoint if it causes jealousies in the ranks. While the mayhem of 2012 has not been repeated this year tensions remain high and several members from both unions have been killed in recent months in gangland-style shootings.

The NUM also says AMCU recruits with threats of violence and intimidation.

AMCU has always denied these allegations and says it has tapped into a deep vein of discontent based on the perception that the NUM's leaders have grown too close to management.

The political stakes are also high as the NUM is a key union ally of the ruling African National Congress, which faces general elections next year.

President Jacob Zuma and his government have been widely criticised for their handling of last year's mining crisis which saw police shoot dead 34 striking miners in a single incident near platinum producer Lonmin's Marikana mine.