Manager Alan Curbishley and chairman Eggert Magnusson are desperate to keep Tevez, who almost single-handedly ensured West Ham's survival in the Premiership last season.
The £6m-a-year offer would make Tevez the highest paid player at Upton Park. But by paying him wages which would put him in the same bracket as Chelsea stars Michael Ballack and Andriy Shevchenko, West Ham hope to convince him to snub offers from Inter and Real Madrid, both of whom are ready to pay Joorabchian £30m.