Malta's ruling Nationalist Party is set to elect a new party leader and prime minister-in-waiting on Saturday in a three-way leadership contest to replace the outgoing Eddie Fenech Adami, who is retiring.

Fenech Adami, 70, is stepping down as party leader and is expected to announce his resignation as prime minister once the tiny Mediterranean archipelago formally joins the European Union on May 1.

The front runner in Saturday's vote by 870 Nationalist Party delegates is Social Policy Minister Lawrence Gonzi, the current deputy prime minister. But commentators predict a tight finish to a two-week campaign which has turned sour in the run-in.

A controversial national poll published this week showed 71 percent support for Gonzi, with Finance Minister John Dalli a distant second with 16 percent.

Angry Dalli supporters said the timing of the poll's release, just days before the vote, was a cynical ploy designed to influence party delegates.

Dalli, 55, claims to have the support of 40 percent of the party delegates.

"My findings are based on what the councillors think, not what the man in the street wishes," he said.

The third candidate, Education Minister Louis Galea, polled just over nine percent, but denies he is a makeweight in the election.

Whoever the party chooses to take over after Fenech Adami's 19 years as leader will continue in the same tradition, according to the Times of Malta.

"Fortunately for the island, each of the three contenders for the post of new PN leader and, eventually, prime minister, shares the same basic conviction, beliefs and values as those of Dr Fenech Adami," said an editorial.

David Kelleher, editor of the Malta Business Weekly, predicts a close contest which could go to a second round next Wednesday if none of the candidates poll two-thirds of the vote.

"It's going to be a tight race. Remember it will be the delegates who vote, not the electorate at large, so the opinion poll shouldn't really have a bearing on the outcome.

"The main reason for Dalli's anger has to do with the fact he believes there has been an attempt to influence the party delegates. There's a lot of political manoeuvering going on," Kelleher told AFP.

This week's poll showed Gonzi as the candidate with most support from the opposition Labour Party, which could be an important factor given Fenech Adami's call, backed by newspaper editorials, for a move away from the confrontational style of politics on the island, whose 380,000 population is effectively split down the middle along party lines.

Gonzi, 50, believes Malta should make the most of its location as the enlarged EU's southernmost member, along with Cyprus.

"We have been trading partners with North Africa and the Mediterranean states since the Middle Ages. We have learnt the ropes of trade and commerce in our region and becoming the southernmost tip of the EU has the potential of transforming Malta as a commercial hub, a tiger economy, in the Mediterranean."

Dalli said EU membership is an opportunity for Malta to become "the capital of the Mediterranean."

Fenech Adami led Malta through a narrow government victory after a bitterly divisive EU referendum campaign last year, but the latest Eurobarometer poll shows support for the island's EU membership at 65 percent, the highest in five years.