The 17-year-old, who joined from Arsenal last summer, is yet to feature for the Hoops first team but has played regularly for their reserve side and has trained with the senior squad.
The Telegraph reports that England are also keen to persuade the Dublin-born player to switch allegiance from the Republic of Ireland.
Okoflex played for the Republic's Under-19 team last month, but also qualifies for England and has previously represented the country at Under-17 level.
He would follow in the footsteps of Declan Rice of West Ham, who made the same switch after featuring three times for the Republic of Ireland as well as winning caps from Under-16 to Under-21 level.
Aston Villa captain Jack Grealish also represented Ireland at underage level before switching to England, who have capped him at Under-21 level.
Okoflex's Celtic team-mate Karamoko Dembele has also trodden a similar path, regularly featuring for both England and Scotland at Under-15, Under-16 and Under-17 levels.