The News of the World says the Portuguese star, 22, will be presented with a deal worth £140,000 a week that would tie him to Old Trafford until 2014.
That would see him leapfrog Chelsea skipper John Terry, who has a contract worth £130,000 a week. Ronaldo, who has scored 27 goals already this season, would earn an incredible £7million a year with his new deal.
Manager Sir Alex Ferguson has only just been given the go-ahead by the Glazer family to break United's wage structure but Old Trafford sources are confident Ronaldo will put pen to paper in the summer.
The winger only signed a five-year deal last season which takes him through to 2012 but Ferguson is keen to reward him for his scintillating form and stunning strike rate that have taken him within reach of George Best's record for a winger of 33 goals in a season.
And United also want to 'ring fence' the player to keep him out of reach of Real Madrid.