English publication 'The Sun' reports that the Spanish international has looked on in envy at the mega-money deals dished out to Paul Pogba and Alexis Sanchez and is now set to demand parity with the club's highest earners to the tune of £350,000-a-week.
De Gea is widely considered the Premier League's best goalkeeper and one of the best in the world, with United aware of the need to do whatever is possible to keep hold of their star man.
Spanish giants Real Madrid hold a long-standing interest in the 26-year-old and United are said to be expecting an approach this summer as Zinedine Zidane looks to freshen up his squad following a disappointing season on the pitch.
De Gea came close to joining Real in a swap deal involving Keylor Navas back in 2015, only for a dodgy fax machine to put paid to the move at the 11th hour.
The former Atletico Madrid man still has 18 months remaining on his contract at Old Trafford, whilst United also hold an option for another 12 months, but it is thought that an offer of a new deal will be forthcoming sooner rather than later as the club look to tie down their key man.