The chief executive of Spain's top lender, Santander, has been barred from working as a banker for three months by the country's Supreme Court due to an earlier conviction for making false accusations.

Today's ruling against  68-year-old  Alfredo Saenz is the culmination of a long-running case, centred around a conviction for false accusations against debtors when he was chairman of Santander-owned bank Banesto in 1994.

Santander said Mr Saenz would appeal against the ban and expressed confidence that he would continue in his role of chief executive at the euro zone's biggest lender, which he has headed for nine years.

Santander's shares were 2.6 per cent lower at €8.1at 11.45am, against a 1 per cent drop in the European bank sector, but analysts said the fall was more related to an earlier downgrade of Spanish sovereign debt by credit rating agency Moody's.

Rumours of a ban on Mr Saenz had been in the market for several weeks, without any significant negative impact on Santander's shares.

The three-month ban is less than expected, and analysts said the ruling was unlikely to lead to a succession battle at Santander.

"I don't think this is going to kick off any change in the top management structure for the time being. Things looked a bit bleaker for Mr Saenz actually a few months ago when the news first came out," Caja Madrid analyst Javier Bernat said.

Mr Saenz will appeal to the Constitutional Court, a bank spokesman said, and ask the provincial court of Barcelona to suspend the sentence.

Under Spanish law, Mr Saenz will be obliged to post a small daily fee while his case is being resolved.

Reuters