Cape Town - Ulster have announced that captain Johann Muller has signed a one-year contract extension, tying him to the club until the end of the 2013/14 season.

According to the Planet Rugby website, Muller, who has been capped 24 times by South Africa since making his debut against Scotland in 2006, has had a huge influence on the Ulster squad since his arrival three years ago.

Muller, 32, has played 52 games for the province to date, and is looking forward to another season at Ravenhill.

"The contract extension has been in the pipeline for a while now and I'm delighted to get it signed. I've had a great time at Ulster so far, three years have flown by and I'm really looking forward to a fourth year," he told Ulster's official website.

"Ulster Rugby has gone through some wonderful times over the past couple of years and it's brilliant to be part of that. The players and back room staff have done an amazing job over the past three years and it's an exciting place to be. Everybody is really happy being part of this squad and this environment and I'm no different. We're on the right track and hopefully we can keep on going and win some silverware.

Ulster are currently top of the Pro 12 standings, 11 points clear of Glasgow Warriors.

In addition to Muller, Ulster's other South Africans on their books are hooker Rob Herring, No 8 Robbie Diack and scrumhalf Ruan Pienaar.