A postal consumer group denied claims that it would advise Royal Mail to end deliveries on Saturday.
A spokesman for Postcomm said: "There is no truth in the suggestion we are going to recommend a reduction in service from six to five days. The status quo is totally enshrined in law."
The group will submit evidence to a review looking at the future of the postal industry. All submissions to that review are due by May 19.
On Friday Royal Mail bosses said they would oppose plans to cut deliveries on Saturday if they were made.
The Post Office has already stopped twice-daily deliveries in an attempt to boost the business.
This week Royal Mail announced a drop in profits and said it had lost £100 million in the last financial year through fulfilling its universal service obligations - its promise to deliver letters to every address in the country for the same price.
