ROME (Reuters) - Former Italian prime minister Silvio Berlusconi called off an appearance on a top television chat show on Wednesday, his second such cancellation this week, raising concerns about his health ahead of national elections.

FILE PHOTO: Italy's former Prime Minister Silvio Berlusconi is seen during the television talk show "L'aria che tira" in Rome, Italy, January 18, 2018. REUTERS/Remo Casilli

Berlusconi, 81, who heads a center-right alliance, played down his absence, telephoning one of his television channels to say he had been worn down by having to select candidates for the vote, but was feeling well.

His bloc is leading in the polls in the run-up to the March 4 parliamentary election and Berlusconi is likely to play a crucial role in coalition talks expected after the ballot.

He has appeared on numerous television and radio shows since last December to campaign for his party Forza Italia (Go Italy!), but he pulled out of an interview with state television RAI on Sunday and scrapped another scheduled show on Wednesday.

La Repubblica newspaper said he was tired and suffering from episodes of high blood pressure. In an unsourced report, it said doctors wanted him to go to hospital for a full check-up, but the billionaire media mogul denied he was ill.

“I am sorry to disappoint our competitors, but I am well. Seriously, I am well,” he said, speaking by telephone to the Matrix current affairs program, which is broadcast by his family-controlled Mediaset company.

But he said he had been under strain last week when Forza Italia had finalised its list of candidates, with existing lawmakers battling to remain part of the team in the face of fierce competition from eager newcomers.

“After working 17 hours a day for five days, changing my mind, making difficult decisions, causing upset and grief, I have taken a bit of a break. They were stressful days. I would say downright painful. But we will now restart the election campaign to win it.”

His party gave no immediate details of when Berlusconi would next make a media appearance or take to the campaign trail.

Berlusconi had open heart surgery in 2016 and regular hospital check-ups and lengthy stays in health spas over the past 18 months. His last public appearance was on Jan. 22, when he went to meet EU officials in Brussels, while his last television interview was on Jan. 16.

Opinion polls suggest his center-right bloc, which includes Forza Italia and the far-right Northern League and Brothers of Italy party, will win the March 4 vote, but will fall short of an absolute majority.

Berlusconi cannot run for public office due to a 2013 tax fraud conviction, but he has presented himself as a moderating force who will keep his allies in check should they win power at the forthcoming election.