Portugal's ruling alliance extends lead in poll before May 18 election

LISBON (Reuters) - Portugal's governing centre-right Democratic Alliance (AD) extended its lead in a new opinion poll ahead of a snap general election on May 18, though the projection showed it still falling short of a parliamentary majority.

The survey by pollster Pitagorica for TVI broadcaster and TSF radio, released late on Monday, put support for the AD at 34.4%, well ahead of the centre-left Socialist Party (PS) on 27.8%.

AD's support increased by about one percentage point from a Pitagorica survey a month earlier, before Prime Minister Luis Montenegro's minority government collapsed in early March, while the PS slipped by the same amount. Other polls mostly put the two parties virtually tied.

Montenegro's government failed to secure a vote of confidence from parliament after the opposition questioned his integrity over the dealings of his family's consulting firm. He has denied any wrongdoing.

A year ago, the AD won the national election with 28.8% of the vote, marginally above the Socialists' 28%.

In the Pitagorica poll, support for the far-right Chega party edged up from a month earlier by 1.4 percentage points to 14.9%, but after scandals involving several senior party members remained below the 18% it won last year.

Since Montenegro refuses any agreement with Chega, analysts see securing support from Liberal Initiative, a small party that shares some of his views on the economy, as his best chance of forging a potential parliamentary majority.

Liberal Initiative is polling at 6%, up from 4.9% in last year's election, but not enough to give a potential alliance with the AD a full majority.

The poll suggests 18.6% of voters are undecided.

Pitagorica surveyed 1,000 people between March 24 and 29. The margin of error is 3.16 percentage points.

(Reporting by Sergio Goncalves; editing by Andrei Khalip, Aidan Lewis)