MADRID (Reuters) - Separatist parties are on track to win a slim majority of seats in Catalonia's parliament in a Sept. 27 election, a poll indicated on Thursday, potentially paving the way for the wealthy northeastern region to declare independence from Spain.
The poll of 3,000 Catalan voters by the state-run Sociological Research Centre (CIS) found that the main pro-independence movement Junts pel Si would win 38.1 percent of the vote, or 60-61 seats in the 135-seat Catalan parliament.
Together with a predicted eight seats for the left-wing, pro-independence party CUP, it would give separatists a very slim majority with 68 or 69 seats.
Separatist parties are portraying the regional election as a proxy vote on independence and have said that winning a majority of seats, and not necessarily of votes, would allow them to launch a "road map" to secession within 18 months.
That is fiercely disputed by centre-right Spanish Prime Minister Mariano Rajoy, who has ruled out a Catalan breakaway.
If the opinion poll results were confirmed on election day, it would give ammunition to opponents of independence -- as they may well argue that a 44 percent share of the vote for the separatist parties and a tiny majority of seats does not give them a mandate to push ahead with an independence campaign.
Tens of thousands of flag-waving supporters of independence are expected to flood the streets of Barcelona on Friday for a march marking Catalonia's national day, which this year will also signal the start of campaigning for the Catalan election.
(Reporting by Adrian Croft; Editing by Paul Day/Mark Heinrich)