The Spanish full-back has fallen down the pecking order at Anfield after multiple seasons of below-par defensive performances since joining from Sevilla in 2014.
According to Portuguese newspaper 'A Bola', the Portuguese giants are looking to replace another spaniard in Alex Grimaldo, who is in high-demand after a stellar season that has seen him attract interest from Europe's biggest sides.
Moreno's liverpool contract is up at the end of the season, meaning the 26 year-old would be able to move to Portugal on a free transfer.
However, Benfica may also face competition for his signature from an unlikely source; Spanish champions Barcelona have been rumoured to be considering a move for Moreno as they look to provide backup for ageing left-back Jordi Alba.
The outbound Liverpool defender last featured for the Reds in their 2-1 FA Cup defeat to Wolves in January of this year.