The anti-establishment Five Star Movement would get 24%.
The poll, based on 1,500 respondents and with a margin of error of 2.9%, indicated that support for the centre-left and the Five Star Movement has ebbed since February 24-25 elections while backing for Berlusconi has risen.
Another poll by the Tecne Institute for news channel Sky TG 24 gave the centre-right 33.3% and the centre-left 31.4%.
The Tecne poll showed that Berlusconi's coalition would fall short of a majority in the Senate, the same problem that the centre-left faces at the moment after winning in February but only by a razor-thin margin.
Berlusconi has urged arch-rival Bersani either to agree to a grand coalition between their two political forces or for new elections to be called.
Bersani has so far ruled out a deal, which would be deeply unpopular among leftists but is supported by some within his own party.
In an interview published on Friday, Berlusconi said he could support a presidential candidate from the left in voting in parliament that will start next week, but only on condition of a cross-party agreement.