LONDON, Oct 1 (Reuters) - Ten-year Portuguese government bond yields fell sharply on Tuesday, with one trader citing talk of a big buyer late on Monday.

"There was a big buyer late last night, so it's an overspill from that," the trader said, adding this was behind the firmer tone in peripheral euro zone markets broadly.

Ten-year Portuguese yields fell 25 basis points to 6.60 percent, while Spanish equivalents fell 6.2 bps to 4.24 percent.

Italian bonds, rattled on Monday by political tensions, lagged most other peripheral debt, with yields only 1 bp lower at 4.56 percent.

Another trader said talk of another long-term refinancing operation, after European Central Bank President Mario Draghi flagged that possibility last week, could also be helping.

The ECB holds a policy meeting on Wednesday.