The 24-year-old started his career at Urawa Red Diamonds in his homeland before switching to the Belgian Pro League in 2021, initially on a loan deal before making the move permanent six months later.
Hashioka has featured 91 times for Sint-Truiden over a three-year period, scoring two goals, with the club currently ninth in the Pro League standings.
The right-back was not selected for Japan's Asian Cup squad in Qatar this month but has experience of playing for his country at senior level, earning seven caps since being handed his debut in December 2019.
According to transfer specialist Fabrizio Romano, Hashioka is edging closer to a move to Luton in the final days of the January transfer window.
The report claims that the defender has flown over to England ahead of medical tests which are set to be held in London before Thursday's deadline.
It is understood that the Hatters and the Belgian club have agreed a £1.71m deal for full-back Hashioka, who has also attracted interest from another English club in recent times.
Championship outfit Leeds United were said to be admirers of the 24-year-old, with Daniel Farke's Whites looking for reinforcements at right-back following the departures of Djed Spence and Luke Ayling.
However, it is claimed that the second-tier side have pulled back in their pursuit of Hashioka due to concerns about his recent injury record.
Rob Edwards's side are short of options on the right side of their backline, being forced to field Chiedozie Ogbene at right-wing-back during their 1-1 draw at Burnley in the Premier League on January 12.
The former Rotherham United striker also operated in that role during the FA Cup successes at Bolton Wanderers and Everton, however it is understood that Edwards is keen to recruit a permanent solution in that position.
Japan international Hashioka certainly fits the description of an attack-minded wing-back, providing four goal contributions in 18 Pro League appearances for Sint-Truiden this term.
Although Hashioka is unlikely to be signed in time to feature against Brighton & Hove Albion on Tuesday night, the defender could make his Hatters debut at Newcastle United on Saturday.