Lebanese authorities on Sunday said two suspects had been arrested in connection with a shipment of millions of Captagon pills confiscated by Saudi Arabia last week.
The drugs bust prompted Riyadh to ban imports of fruits and vegetables from Lebanon due to concerns they were being used to smuggle narcotics.
"The investigation into the Captagon smuggled into Saudi Arabia is nearing its conclusion and we have arrested two brothers," caretaker interior minister Mohamed Fehmi told the local news station MTV.
The Saudi import ban has driven down the price of local produce in Lebanon by as much as 40 per cent and cut farmers off from a source of revenue at a time of severe economic stress.
Saudi authorities said last week that they had seized 5.3 million Captagon pills and 2.4 million amphetamine tablets hidden inside pomegranates imported from Lebanon.
The ban will remain until Lebanon provides "adequate and reliable guarantees" that it is taking action against drug traffickers, the Saudi Interior Ministry said.
The Lebanese Army raided Captagon factories in the Bekaa Valley, which is controlled by the Iran-backed group Hezbollah.
Mr Fehmi said he "cannot confirm that Hezbollah is involved. We must wait for the results of the investigation".
His comments came during a visit to the region of Akkar, north of the Bekaa Valley, on the border with Syria.
The head of the Bekaa Farmers Association said the shipment only passed through Lebanon from Syria.
The Syrian government, an ally of Hezbollah, has been suspected of involvement in the amphetamine trade.
In July, Italian police seized the largest Captagon shipment on record, worth €1 billion ($1.2bn), which came from the Syrian port of Latakia.