Prosecutors seeking a lengthy prison term for Costa Concordia skipper Francesco Schettino summed up their case Tuesday by saying there was a "tsunami of evidence" against him.

Schettino's 19-month trial will come to an end on Wednesday or early Thursday, just over three years after a disaster which left 32 people dead and led to the ship's captain being charged with multiple manslaughter, causing a shipwreck and abandoning his stricken vessel.

Prosecutors have asked judges to impose a sentence of 26 years and three months for the man dubbed Captain Coward over his actions in the aftermath of the giant liner striking rocks off the Tuscan island of Giglio on the evening of January 13, 2012.

"Against Schettino there is a tsunami of evidence," said prosecutor Stefan Pizza, urging the judges to convict before adding: "It is easier for a lawyer to fly than to defend Schettino."

Schettino told reporters he would be in the court to hear the verdict and would make a statement afterwards.

His defence team concluded their arguments on Monday by insisting that Schettino, 54, could not be held almost exclusively responsible for the disaster and arguing that his conduct may actually have prevented a greater loss of life.

In particular, Schettino's lawyers have attacked the prosecution's assertion that he negligently delayed issuing an order to abandon ship after it was holed below water and began to tilt dangerously.

They say the skipper had correctly calculated that the prevailing tide and wind conditions would carry the listing ship towards the shoreline, at which point an evacuation order would be much safer and quicker to implement.

Schettino testified earlier in his trial that he had wanted to avoid a general panic resulting in passengers throwing themselves into the water.

He blames his crew for failing to alert him to the rocks and says the primary cause of the 32 deaths was the fact that the ship lost all power because of the failure of a back-up generator, for which he cannot be held responsible.

The captain has defended sailing close to Giglio as standard practice intended to impress passengers which was encouraged by the company.

He also disputes abandoning ship, saying he fell off as a result of it tilting. The prosecution's prison request is based on him getting 14 years for multiple manslaughter, nine for causing a shipwreck, three for abandoning ship and three months for lying to maritime authorities.

Whatever the outcome, Schettino will not go to prison immediately. Under Italian law he is entitled to two appeals before he would have to begin any prison term.