LISBON (Reuters) - Portugal's ruling Socialists extended their lead in a new opinion poll ahead of an Oct. 6 parliamentary election, and were also well ahead of the opposition in another survey published on Friday, although the party remained short of a majority.
Prime Minister Antonio Costa's centre-left party received 38.4% of voting intentions in the survey by pollsters Aximage for the Jornal Economico newspaper, up slightly from 38.1% in Aximage's previous survey last month.
Another poll, the first by Intercampus for the Negocios newspaper, put the Socialists at 37.9% ahead of this election. In the 2015 election, the Socialists finished second with 32%.
The main opposition Social Democrats were seen taking 20.6% of the vote, among the lowest scores in any recent survey and down sharply from nearly 37% in the 2015 ballot, according to Aximage. Intercampus put them at 23.6% of voting intentions.
Under Portugal's proportional representation system, an absolute majority has previously been achievable with 42% to 45% of the vote, but some analysts say that threshold could drop to 39-40% due to a growing distance between the top two parties and emergence of a new relevant player.
If the Socialists fail to win full majority they would need the support of another party to pass legislation.
The Socialists came to power in 2015 with parliamentary support of two hard-left parties, the Left Bloc and the Communists. These parties saw support at 10.2% and 5.4% respectively in the Aximage' poll.
Just one ally is now likely to be needed to secure a majority, and analysts say souring relationships with the hard-left could prompt Costa to find a new partner, the People-Animals-Nature party (PAN). According to Aximage, it would grab 4.9% of the votes; Intercampus gave them 5.2%.
Intercampus surveyed 801 people on Sept. 2-11, with a margin of error of 3.5%. The Aximage poll was carried out on Sept. 1-8 and surveyed 985 people. It had a margin of error of 3.10%.
Following is a table with recent opinions polls. Note: PS - Socialist Party, PSD - centre-right Social Democrats, CDS/PP - conservative right, CDU - Communist-Greens alliance.
(Reporting by Andrei Khalip and Catarina Demony; Editing by David Gregorio)