The data, released by pro-independence Scottish newspaper The National today, suggests a late surge for independence, following October’s illegal referendum.
Polls are notoriously unreliable and the last official poll suggested a closer race.
But The National’s projections – which have shown a shift towards independence over the last few days – suggest independence parties could take a majority of between one and five.
Their unofficial poll predicts independence parties will win between 69 and 73 seats, with only 68 required for a majority.
Last Friday, the final official poll suggested that pro and anti-independence parties were neck and neck, with a hung parliament likely.
Such an outcome could trigger weeks of uncertainty, as parties negotiate in an attempt to form a coalition.
However, today’s poll, based on more recent interviewees with 1,000 people, suggests independence parties could yet take an unlikely majority.
It also suggests some 25% of voters remain undecided.
Turnout is expected to be a record high of over 80%.
Ciudadanos, Ines Arrimadas’ pro-Spanish party, are widely expected to win most seats but be outnumbered by rival pro-independence parties working together.
Ousted president Carles Puigdemont’s Junts per Cataluña party are expected to finish third. Imprisoned vice-president Oroil Junqueras’ ERC party are set to be second.
Last Friday’s poll was the final official forecast. Rules meant to minimise polling’s impact on the result forbid further official polls in the days before an election.
Meanwhile, security has been boosted ahead of the elections, with an additional 5,000 officials on duty than for normal regional elections.
Support for independence has hovered at around 50% for some time.