LISBON (Reuters) - Portugal’s ruling centre-left Socialists extended their lead in an opinion poll published on Monday, putting them close to the level needed to win an absolute majority at a general election in October.

The poll, carried out by the polling agency Pitagorica for the radio station TSF and the newspaper Jornal de Noticias, put the Socialists at 43.2%, up from 40.4% in May.

The Socialists’ score was among the highest they have had in any recent survey. If the performance is repeated in the general election, they could win an absolute majority and govern alone, without their far-left allies.

Under Portugal’s proportional representation voting system, an absolute majority is achievable with 42% to 45% of the vote. Majority rule for the Socialists could help the government to maintain policies to balance the budget and attract more foreign investment.

Another poll, published on Friday, gave the Socialists 37.5% support.

Monday’s poll gave the main centre-right opposition, the Social Democrats, 21.6% support, down from 22.5% in May.

Both of the government’s far-left allies gained in the poll, with the Left Bloc rising to 9.2% from 8.2%, and the Communists advancing to 6.8% from 6.5%.

The Pitagorica poll was carried out between July 8 and 14 and surveyed 800 people. It had a margin of error of 4%.