Out-of-contract Njazi played alongside his brother for German second-division side TuS Koblenz last season, before Shefki moved to Swansea in January.
"It would be a dream for us to play together at Swansea, we are very close as brothers and can read each other well," Shefki told the Swansea website.
"But we are different footballers. Although he is tall like me, he prefers to have the ball at his feet. I'm better in the air."
Njazi began his career with Finland's FC Lahti in 2002, won his first cap in 2004 and moved to the Premier League with Birmingham the following year.
After struggling to establish himself and loan spells at Blackpool and Peterborough, he was released in 2006 and joined up with Dutch side FC Groningen.
Next came German side FC Carl Zeiss Gena, before he signed a three-year deal with Koblenz in 2007, winning two more caps during his time with the club.
"It's good to link up with Shefki again," said 6ft 4ins Njazi.
"I've enjoyed the training so far and the whole squad has made me feel very welcome."
Source: BBC Sport
Source: BBC Sport