How strong was Zeff?

[SSJ2]

Sanji says he would have been able to solo Krieg's crew. He survived the Grand Line for a year. Would he match up against Alabasta level fighters?

 

[Captain Cadaver]

From what we know, he was fighting on the Grand Line since Roger's execution and established a fair reputation. In his prime, I wouldn't be surprised if he could give Part 1 Sanji's peak power a good challenge. As for himself at the start of the series, he was suggested to be stronger than East Blue Luffy physically since he hurt Luffy with a kick from his wooden leg. Could be an implication that Zeff also has Haki, though I think that could be a stretch, since Haki only seems common amongst New World pirates.