The telecoms regulator Ofcom has announced it wants to cap the price of 118 directory enquiry calls at £3.10 for a 90 second call.
Market leader 118 118 charges £11.23 for a 90 second call to its service.
Ofcom said providers had been increasing prices “quite significantly” in recent years and that people are paying much more than they expect.
Overall 2% of adults or one million people use a 118 service, rising to 4% among those over the age of 65.
Ofcom launched its enquiry into the cost of 118 calls in May 2017.
It last investigated the sector in 2013 when the price was about £3 for a 90 second call.
At that time it said there was not much evidence of “bill shock”, which is where people are unpleasantly surprised when they receive their bill.
Now however, it said some people were suffering “bill shock”.
It said it was now most appropriate to “bring prices down to 2013 levels”.
The second biggest provider, BT cut the price for its 118 500 number on the 1 June to £3.10 for 90 seconds, down from £6.88.
In a statement Ofcom said: “We’re concerned about rising prices for directory enquiries, and callers paying much more than they expect.
“So we’re taking action to protect consumers by proposing a cap on the cost of 118 numbers.”
Ofcom’s consultation will run until 22 August with a decision due at the end of the year.