The Welsh have touched down just once in their two November Tests and have scored only two tries at home this year with Leigh Halfpenny scoring both.
Williams, Wales' record try-scorer, said: "It is a little bit of a concern, we are creating things but we're just not finishing off tries at the moment.
"We haven't hit the panic button yet as we have players behind the scrum who score tries week in, week out for fun."
Halfpenny scored in Wales' 23-15 victory over England at the Millennium Stadium in the Six Nations rugby and the Cardiff Blues wing also scored in last Friday's 17-13 win over Samoa.
But the once prolific Welsh failed to cross the line in defeats to Ireland and New Zealand.
Wales, though, scored seven tries on the road in the Six Nations rugby while an under-strength tour party scored eight tries in summer tour Tests against Canada and United States.
The Welsh are renowned for their attacking rugby, but the lack of a cutting edge is worrying Williams and his coach Warren Gatland.
His men created almost a dozen try-scoring opportunities against Samoa on Friday but Wales hope to convert chances into scores in their Saturday's showdown with Argentina in Cardiff.
"In Test match rugby you don't often get many chances," Gatland said. "And if you do, you have to take them.
"We created a huge amount of chances against Samoa and could have scored four or five tries.
"And of the two autumn games, we played more rugby than the opposition as they kicked the ball more.
"We are a little bit frustrated ourselves that we haven't scored more tries in the two matches but the defence has been good.
"We are creating opportunities and we need to finish them off."
Wales conceded just two tries in their 2008 Grand Slam triumph when the free-scoring Welsh touched down 13 times in their second clean-sweep in four years.
Williams' six tries in five Six Nations rugby matches - equalling Will Greenwood's Championship try-scoring record - earned him the player of the tournament award.
The Ospreys star scored nine tries in 2008 and was honoured with the IRB International Player of the Year accolade.
Wales, however, have lacked a killer instinct recently but Williams says creating chances is not the problem.
"We certainly showed against Samoa that we can create things," said the 32-year-old who boasts a prolific strike-rate 46 tries in 66 caps.
"We made 11 line breaks and just one try - from a kick as well. Maybe the Welsh public expect a bit more.
"There is a little bit more pressure on the outside as we all know Welsh supporters expect tries and expect great games - but it isn't always the case.
"We've got to take ownership of individual errors which didn't allow us to capitalise on the hard effort and work we put it in," said Wales captain Ryan Jones.
"We made 11 line-breaks and scored just one try which is unusual for us. We've always thrived on that small opportunity or on an opposition mistake - and that, for whatever reason, is something that has gone out of our game."
But Stephen Jones, the Lions fly-half, insists the scores will come.
I like to take people on and run from my own line and, if England do not agree with that style of rugby, I am not their man." England may not be playing well, but their two home matches in next year's Six Nations hospitality are already sell-outs and all the hospitality for the first game, against Wales in February, have been taken. Australia and New Zealand are not so fortunate commercially and they will express their concerns about the stagnancy of the game on the field at this weekend's gathering of the International Rugby Board's general assembly in Dublin, followed by a meeting of the council.
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