Czekaj was hailed a 'star in the making' after scoring an outstanding 60 metre try for Wales on his debut against Canada in June 2005 aged 19-years-old. He then toured with Wales to Argentina in the summer of 2006 and made his RBS Six Nations debut against Ireland in 2007.
Nick Macleod was also called up to the Welsh squad that toured Argentina last summer, having impressed the selectors with his appearances for the Blues.
Stcherbina has been one of the most consistent players for the Cardiff Blues since joining from Northampton Saints in 2005. He has featured in 18 of the 23 matches played this season. The 30-year-old began his career playing for the Super 14 outfit NSW Waratahs as well as representing Australia A and Sevens before moving to Europe to play for Biarritz.
"Having quality players such as Chris, Marc and Nick signing extensions to their contracts is a real boost to the team," said Director of Coaching Dai Young.
"Marc has settled in well since his arrival and has been one of our most consistent players over the last two seasons. The experience he brings to our backline is invaluable. Chris and Nick have come on leaps and bounds over the last two seasons and the coaching team are really happy with the progress they have made," Young added.