US iTunes users can expect more movie studios to release their flicks through the service - but not until after Christmas, an analyst claims.

Piper Jaffray analyst Gene Munster told clients in a research report released yesterday that at least two studios plan to release movies through the service "within six months".

He believes that threats of retaliation by competition-shy DVD box retailers, copy protection worries and the desire for flexible prices and studio control of such prices have been sticking points for getting more movie houses onto the iTunes trail.

Studios are particularly concerned that retailers like Target and Wal-Mart may make good their threat to minimise DVD sales in the event that online services offer films at lower prices.

The analyst also describes studio demands for more control on the price Apple charges for their movies as a major sticking-point to success, Apple Insider reports.