The Daily Record claims Ayunga will become Robinson’s fourth summer signing, making the move on a two-year contract.
He left Bristol Rovers for Morecambe last July, becoming one of 19 summer arrivals in the aftermath of promotion to League One.
However, he was one of 10 players made available for transfer by manager Derek Adams when the club published its retained list last week.
Usually playing as a wide striker, Ayunga made 42 appearances in all competitions during 2021/22.
However, his last nine outings all came off the bench with Dylan Connolly and Arthur Gnahoua usually flanking Cole Stockton.
Those 42 games also brought six goals, scoring home and away against Wycombe Wanderers, twice at Accrington Stanley, once against Plymouth Argyle and the injury-time equaliser against Portsmouth on Easter Monday.