Tolls on the Severn bridges have gone up again, prompting fresh criticism of their impact on the Welsh economy.
Charges are now £6 for cars, £12.10 for vans and £18.10 for lorries, following the annual New Year increase.
Some MPs want the UK government to discuss ways of reducing the charges with the private operator but others say it cannot be done.
Meanwhile residents of the Forest of Dean have called for discounts for people living near the crossings.
Martin Evans from the University of Glamorgan Business School told BBC Radio Wales the charges were having a negative impact on economic activity on the Welsh side of the crossings.
"When you have a bridge with a toll across it, it is a restriction on economic activity on both sides," he said.
"But in this instance we probably suffer more than the English side do."
He said a complicating factor was that although transport and economic development had been devolved to Wales, the UK government had responsibility for the bridges.
The crossing are due to pass into public ownership in five years' time.
Swansea West Labour MP Geraint Davies believes it is possible to lower the tolls now.
He said: "It's a matter of the government sitting around the table.
"The bottom line is from 2017 we will be able to reduce the tolls from £6 to around £1 just to cover the operating and maintenance costs."
He said there was an incentive for the UK government to do so earlier as increased economic activity would result in higher taxes for the Treasury.
"What I think the government should do is firstly announce from 2017 there will be a substantial reduction once it goes into public ownership.
"The government could pay up front some of the money to get tolls down in order to reap the rewards sooner rather than later at a time when we urgently need inward investment."
Monmouth MP David Davies, who chairs the Welsh Affairs Select Committee, said its members had already made a number of recommendations about future charges.
"The only way we could do it [drop charges now] would be to pay vast amounts of compensation to the company that built the bridge," he said.
"Where I absolutely agree with Geraint is we can do something about this in 2017 because the original amount of money that was agreed for paying for the bridge will be paid off.
"Then we could go back to a much lower price."
Meanwhile residents living in the Tidenham and Tutshill areas of the Forest of Dean in Gloucestershire are calling for a local discount following the annual toll rise.
John Powell from Tidenham parish council said: "For those in the parish who work over in Bristol and have to use the crossing it's an impingement on them.
"Recently one or our friends had to go to a Bristol hospital to have chemotherapy about three or four times a week for quite a considerable time and at £6 a time it was a very, very expensive exercise from which you have no recourse to reimbursement of the costs."