Wolves are reluctant to lose Nunes so close to the end of the transfer window
Premier League leaders City had a £47m bid for the 25-year-old Portugal international turned down last week.
However, Wolves are expecting an improved offer before Friday night's transfer deadline.
Nunes did not attend training on Sunday or Monday and did not have permission to be absent from manager Gary O'Neil.
It is understood Wolves want in excess of £60m for Nunes, who has made it clear he wants to join Pep Guardiola's side.
The Midlands club signed the player on a five-year contract last summer, paying a club-record £38m to Sporting Lisbon.
Nunes was a key figure during the second half of last season as Wolves successfully avoided relegation, finishing 13th in the table.
-- Courtesy of BBC Sport