YES Scotland is under pressure to publish the results of polling research claiming support for independence is rising among women, 16 to 24-year-olds and parents with young children.
The pro-Union Better Together campaign says rules governing polling state the full results must be published.
The Yes Campaign insisted the rules did not govern internal research findings, but Better Together campaign director Blair McDougall said: "This looks like a rookie campaigning error but it has serious consequences for Yes Scotland.
"The rules are clear: if you publish results from your private polling you must publish the full results. You cannot make some polling results public, but then claim it is private."
Findings from the Yes campaign's internal polling research, reported in The Herald, suggested there was now a majority in favour of independence among 16-24 year-olds. However, Better Together said recent public polling put the percentage of this group in favour of a Yes vote at 21%.
Similarly, claims of majority support for independence among families with young children of a shift among female "don't know" respondents towards a Yes vote were questioned.
Mr McDougall added: "While every public opinion poll has shown support for separation falling since the launch of Yes Scotland, the Nationalists claim they have a poll that shows the opposite. Let's see it.
"The regulations say that if Yes Scotland's pollster is a member of the British Polling Council they must now publish their full tables.
"Given their confident statements in The Herald we are sure Yes Scotland will be keen to publish to prove how much support they have among the Scottish people."
A spokesman for Yes Scotland said: "Clearly, the No campaign does not understand the difference between private research and public polling, but it is interesting they do not challenge our research findings regarding more women and young people coming to Yes."