By Paul Lewis
BBC Radio 4's Money Box
The website says MoneySense gives "straightforward, impartial guidance"
The Advertising Standards Authority is investigating NatWest's television adverts which promise 'impartial money guidance'.
The move follows complaints from the public which are supported by research from the consumer organisation Which?.
It claims on 16 out of 20 occasions the guidance changed into 'a slick sales pitch' for NatWest's own products.
NatWest has denied the claims and said its advisers do give impartial guidance and customer satisfaction is high.
Dominic Lindley, principal policy adviser at Which? told BBC Radio 4's Money Box programme: "Our investigation has revealed that NatWest's MoneySense service isn't always delivering the impartial advice it promises."
He continued: "Consumers are told if they make an appointment at a NatWest branch with a MoneySense adviser they will receive impartial guidance. But sometimes they're actually on the edge of a slick sales pitch instead."
Which? sent mystery shoppers to ask the same questions to MoneySense advisers in 20 NatWest branches.
The recorded interviews showed that on only four occasions were they given what Which? considered to be impartial guidance.
In the other 16, the adviser either spoke exclusively about NatWest products, or transformed into a sales adviser and recommended NatWest products, or passed the customer on to a colleague for sales advice.
'Abuse' of trust
A NatWest spokeswoman told the programme: "If a customer wants specific advice on a product then they hand them over to a customer service person or end the MoneySense session and start a separate session talking about products."
But Dominic Lindley said that breaches the trust of consumers and can result in inaccurate advice.
"They might say they have particular products, claim they have the best rate, and then try to persuade consumer to take up that product," he told the programme.
"[One adviser] claimed their ISA Plus had the best rate but when we did the research it was in fact Barclays."
Chris Cummings, director general of the Association of Independent Financial Advisers, was also critical of the MoneySense service.
"It is a complete abuse of consumers' trust. It is the banks trying to masquerade as one thing in order to generate sales. That is not the way to repair the reputational damage the banks have suffered," he said.
NatWest said in a statement: "These sessions are impartial and we have received excellent customer feedback. We regularly conduct our own internal reviews of the MoneySense Service and this [Which?] report certainly does not reflect our experience."
BBC Radio 4's Money Box was broadcast on Saturday, 9 May 2009 at 1204 BST.