Supporters are urging the Welsh Rugby Union to clamp down on touts selling tickets for the Grand Slam clash with Ireland at up to 10 times face value.
The Millennium stadium is a sell-out for Saturday's game
Tickets for Saturday's match in Cardiff are changing hands on internet action sites for up to £250 each.
Although the WRU has urged people not to buy tickets from touts, it said sellers were not breaking the law.
But officials said fans who are without a ticket should either stay home or watch the match at the pub.
It is illegal to re-sell tickets for football games due to crowd trouble fears but the same rule does not apply to rugby.
Saturday's showdown at the Millennium Stadium has been a sell-out for weeks with official ticket prices ranging from £14 to £42.
But scores of tickets can be bought on internet auction sites at hugely inflated prices. One ticket has even been advertised on one site at £2,000.
Rugby fan Kevin Jones from Laugharne in Carmarthenshire said: "How do these people, who are not true supporters of their country, get the chance to have tickets when they have no intention of going.
"The people selling the tickets are only out to make a profit.
"I am sure there are hundreds of Welsh supporters being denied the opportunity to watch Wales play."
Paul Sergeant warns fans buying from touts will be disappointed
The Welsh Rugby Union said it clearly stated on each ticket that they are not to be re-sold above face value.
A spokeswoman said: "It is against the rules to sell tickets above face value without our consent however it is not an illegal practice in law."
She said that, where possible, the WRU would attempt to trace the source of tickets on the black market and would take action against those found selling tickets at a profit.
"We will be reviewing the situation after the Six Nations," she added.
"We would urge people not to pay over face value for tickets.
"There were people who left the game against in England in tears because they had bought tickets that were stolen and had to leave."
Stadium manager Paul Sergeant also warned against buying tickets from touts or over the web.
"You're going to get your fingers burnt, " he said.
"You run every risk of buying tickets that are either forged or stolen.
"My advice is if you haven't got a ticket either stay at home or go and watch it in the pub."