Israel provided no evidence of cross-border attack tunnels in a meeting with UN peacekeepers on Wednesday, Lebanon's Parliament Speaker Nabih Berri said.
The Israeli military launched an operation on Tuesday on its side of the border to "expose and thwart" tunnels into its territory, which it said originated from Lebanon.
Israel accused Lebanon's Hezbollah movement of digging across the common frontier, saying they did not function yet but posed "an imminent threat".
There was no comment from Iran-backed Hezbollah.
"The Israelis did not present any information," at the meeting with the Lebanese army and the UNIFIL peacekeeping force, a statement from Berri's office said, adding that geographic coordinates had been demanded but not received.
"This (Israeli accusation) is not based on any real facts at all," Ali Bazzi, a lawmaker from Berri's parliamentary bloc cited the speaker as saying after a meeting.
Mechanical diggers, drills and other heavy machinery were seen from south Lebanon throughout Tuesday, working on the Israeli side of the heavily-guarded border. Prime Minister Benjamin Netanyahu said late on Tuesday the operation would continue for as long as necessary.