Officers cuffed local politicians from both the left and right, including regional councilor Luca Gramazio from Silvio Berlusconi's Forza Italia party, accused of serving as a go-between for corrupt businessmen and the mob.
The investigation, lead by Italy's anti-mafia police, also focused on 21 other suspects whose businesses or offices were being searched on Thursday.
The arrests were the second stage in a probe which saw one-eyed boss Massimo Carminati and 36 others, including a former mayor of Rome, arrested in December.
Police believe that as well as rigging contracts given out by municipal authorities, the mafia network also conspired to skim off cash from centres established to house asylum seekers and recently-arrived migrants.
The network, "by means of corrupt practices and collusion, assured itself numerous contracts and financing from the Lazio Region, the Rome municipality and associated businesses," the police said in a statement.
The gang got its hooks into everything from Rome's recycling and garbage disposal, to maintenance of parks and cycling paths and bad weather response.
Rome's mayor Ignazio Marino welcomed the arrests, saying "politics in the past gave a bad example, but today... we have honest people who want to restitute quality of life and all the rights and dignity the capital deserves."
But the raid was immediately held up by the head of Italy's anti-immigration Northern League party, Matteo Salvini, as an example of the incompetence -- or worse -- of Prime Minister Matteo Renzi and Interior Minister Angelino Alfano.
"Another 44 people arrested for the immigration business. Stop the departures and the boats immediately, stop the contracts right now!" he said on Facebook.
"It's nothing to do with being good-hearted, welcoming and supporting... they are thieves! Renzi and Alfano scatter illegal immigrants in the hotels of half of Italy, guess who gains?" he said.