The 27-year-old started his career with Llanelli Scarlets before joining Brive on a two-year deal in June 2008.
He has had spells with the Ospreys, London Welsh, Scarlets and the Dragons since returning to the UK.
Blues director of rugby Phil Davies told the club's official website: "Liam is a player that I am familiar with having coached him as a 19-year-old with the Scarlets.
"He is a very talented scrum half who has a great pass, a good kick and does the basics well.
"He played alongside Andy Goode in Brive and has come home looking for an opportunity to play.
"He will give us extra cover at scrum half for the rest of the season with Rob Lewis having returned to London Welsh on a loan spell."
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The entire All Blacks apparel line has been updated for 2013/14. Check out the New Zealand All Blacks polo.
The Nike Tiempo is a solid rugby cleat and one of few styles still made from full-grain natural leather.
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The All Blacks Performance t-shirt is black with hints of blue from the training jersey. Very Cool.
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The NEW All Blacks 2013/14 jersey has arrived at World Rugby Shop. Dare to wear the colors of the All Blacks.
