Rugby officials have blamed a "blip" for 20,000 empty seats for Wales' opening autumn international against Australia at the weekend.
Just 53,127 attended the match at the Millennium Stadium on Saturday, one of the lowest against a leading nation since the arena was built.
Welsh Rugby Union group chief executive Roger Lewis said it was the medium price range of tickets failing to sell.
But sales are looking better for the other autumn fixtures, he added.
Only the 27 November fixture against New Zealand is sold out, with South Africa and Fiji still having capacity.
But the WRU says more than 50,000 tickets have been sold for the South Africa game on 13 November.
Mr Lewis said the WRU is investigating ways of filling the 74,500-seater stadium at the less popular fixtures, especially during the current tough economic climate.
He confirmed family tickets priced at less than £60 will be available for the first time.
But he argued the turn-out should be viewed in a historical context and was just a "blip".
He told BBC Wales: "It's always very tempting to draw quick conclusions in these circumstances.
"Yes there were 53,000 people at the game but historically that is not a shock.
"In 2009 against Argentina and Samoa we had 53,000 and 58,000 and in 2007 we welcomed 56,000 to watch South Africa.
"In 2007 we had 48,000 to the Rugby World Cup warm-up against France and during the last recession in 2001 and 2002 we did not sell out any of the autumn test matches including New Zealand."
Tickets in the top and bottom price brackets always sell out fast, Mr Lewis added.
But it is the £40 medium range tickets that are not being snapped up.
He said: "During all our Six Nations we will sell out.
"Prices will be lower for the Fiji game. We can set prices as we think appropriate, but we have to ask why are people not wanting to make the purchase for the £40 tickets.
"We will put in place family packages and we will have a free training session so people can come and see the team train."
The poor ticket sales follow concerns voiced by English clubs' chief Mark McCafferty.
He said last week: "We would hate to go the way cricket has gone and find there is such a proliferation of international matches that their importance is lost.
"International matches are top of the tree, it is your premium contest. There is a danger for all of us to go for volume over quality."
Mr Lewis rejected that argument and said international rugby funded the game at all levels in Wales, from grass roots to regional.
But Jeff Skidmore, chairman of Loughor Rugby Club, said the games are being scheduled too frequently and the tickets are over-priced.
He said: "We knew we were having problems by September when orders were down and sponsors weren't interested.
"I think the WRU could have known this when they were considering the pricing back as far as April."
Former Wales rugby union and league international John Devereux said the atmosphere at the match was "okay" but the empty spaces in the stadium were very conspicuous.
He criticised the WRU for spending lots of money on advertising at a time when people were struggling to pay for tickets.