A report by Mundo Deportivo has claimed the A-League newcomers are deep in talks with the midfield duo and are only waiting on the approval of work visas before a deal can be made official.
It would be Susaeta's second stint in the A-League with the 32-year-old playing 10 games for Melbourne City last season, scoring two goals and providing one assist.
The right-winger was released by City in July to allow him to return home to Spain with his family due to the global coronavirus pandemic.
33-year-old central midfielder Benat, who made 187 appearances in La Liga with Real Betis and Athletic Bilbao, is currently a free agent after his contract with the basque club expired.
Susaeta and Etxebarria were teammates at Bilbao for six seasons between 2013-2019 and helped guide the club to Spanish Super Cup honours in 2015 with a 5-1 win against Barcelona.
Both have international experience as Benat has played four times for Spain, while Susaeta has one national team cap to his name.
The pair would add international experience to Ante Milicic's Macarthur squad for their debut season which already includes former Socceroos captain Mark Milligan, as well as fellow Australian team representatives Adam Federici, Ivan Franjic and Tommy Oar.
Macarthur's squad so far
Goalkeepers: Adam Federici, Nick Suman.
Defenders: Aleksandar Jovanovic, Aleksandar Susnjar, Ivan Franjic, Jake McGing.
Midfielders: Jake Hollman, Michel Ruhs, Mark Milligan, Loic Puyo, Liam Rose, Antonis Martis, Denis Genreau.
Attackers: Tommy Oar, Moudi Najjar, Matt Derbyshire, Milislav Popovic
