The Italian, who has been linked with a possible exit from the Etihad Stadium at the end of the season, has claimed that his side's Premier League title push has been hampered by the club's failure to clinch the signings he wanted.
City, who snatched the league title last season in the dying minutes of the campaign, are currently 15 points behind leaders Manchester United.
"Mancini continues to talk about City's failure to sign the players he wanted last summer, top-class performers such as Robin van Persie, Daniele De Rossi and Javi Martinez," Hansen wrote in The Telegraph.
"But the fact that none of those players arrived and Mancini chose to stay suggests to me that he is at fault for still being there. The minute a manager fails to persuade his bosses to get the players he wants is the minute he should go."
Mancini is preparing his side to face United at Old Trafford tonight.