The midfielder has impressed in his first four games for Newcastle and earned comparisons with one of the club's former stars
Shelvey joined Newcastle from fellow Premier League strugglers Swansea City last month, and the England international has already impressed his team-mates.
So much so that Sissoko has likened the former Liverpool prospect to France international Cabaye, who left St James' Park for Paris Saint-Germain in 2014 before linking up with Crystal Palace.
"I really believe that he is the replacement, two years after [Cabaye's departure]," Sissoko said.
"Jonjo, like Yohan, is a very good player. He sees the game so easily and delivers great balls.
"For me, he is the same style as Yohan and has the same qualities so for me, yes, he is an excellent signing for us.
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"He has now played four games for us and you can see what he brings to the team. It has to be good for us."
Shelvey played a key role in Newcastle's 1-0 win over West Brom on Saturday, with the new signing setting up Aleksandar Mitrovic for the game's only goal in the 32nd minute.
The result helped Newcastle out of the relegation zone and a point clear of the drop.
Sissoko added: "Now we have to grow with him, make sure we make the most of his vision and his range of passing to pick up as many points as we can between now and the end of the season.
"When we lost Yohan, the club did not bring in another player like him. There was a gap.
"We still had good players like Cheick [Tiote] and Jack [Colback] but they are very different styles. They were not like Yohan.
"With Jonjo, he is the perfect style for us because he fits in so well. Players like myself and Gini [Wijnaldum] like to go forward and he can pick us out so easily.
"It makes such a difference and now we must feed off him. It worked against West Brom with Jonjo spotting Mitro [for Mitrovic's goal] and it will happen again.
"He has already become a very important member of this team because he is different."