Independent record labels have made a complaint to the Office of Fair Trading (OFT) in a bid to stop changes to the official UK singles chart.
The first Top 40 to include download sales will be revealed on Sunday
The Association of Independent Music (AIM) said the combined download and CD chart launch on 17 April is "extremely premature".
Indie music's absence from key retail outlets and a lack of download sales figures have prompted AIM's concerns.
The Official Charts Company (OCC) has called the complaint "unfounded".
They have said that this Sunday's combined chart is likely to feature eight indie songs - two more than is predicted to appear in the conventional countdown.
Alison Wenham, chief executive of AIM, said they approached the OFT only after the organisation had "exhausted all other options".
"We have been very concerned for some time that the date set for the launch of the combined chart is extremely premature, given the rather tentative supply chain structure at the moment, and that has failed.
"It's quite clear from every aspect we examine this that the chart is premature to be launched as an official chart, which is a barometer of consumer tastes," she said.
Tony Christie (left) is tipped to top the first combined Top 40
Ms Wenham added that a number of retailers had failed to deliver download data this week.
But she also said independent labels stood to benefit from the new countdown when the supply chain was robust enough for it to go public, which was a "very exciting" prospect.
The OCC have said they are "confident" its development of the new chart in the past 18 months in conjunction with both small and large record companies will "maintain high standards of accuracy".
The organisation added the official UK singles chart "continues to be the most accurate in the world".
It added it would comment further on the claims after seeing a copy of AIM's full complaint.
Independent labels have already expressed concerns that major competitors may use the download charts to massage sales figures, revealing a lack of security in the system.
The OCC said "hyping" in the download market will lead to a ban for any label caught chart-fixing, and it is "pretty confident" about security.
Early indications suggest Tony Christie's (Is This The Way To) Amarillo will become the first number one in the combined chart, following four weeks on the traditional sales rundown.
Several singles are expected to climb the chart as a result of download and shop sales being collated together for the first time.
Separate charts for over-the-counter and download sales will continute to be published alongside the combined hit parade.