The men jailed over the grounding of the cargo ship Rena off the Tauranga coast have been released today.

Ship captain Mauro Balomaga, 44, and navigator Leonil Relon, 37, were sentenced to seven months' jail in May for operating a vessel in a manner likely to cause danger, discharging a contaminant and altering ship documents.

With sentences under two years, the Filipino men were to be automatically released after serving half of their jail term.

Balomaga's lawyer Paul Mabey confirmed the pair were being released from Waikeria Prison today and would be deported to the Philippines tomorrow.

"They leave the prison and then go into custody of Immigration. Then Immigration sees them off to home," he said.

Balomaga and Relon were keen to see their families again as it had been "a long time".

"I just know they are looking forward to getting home," Mabey said.

The men were charged under the Maritime Transport Act, Resource Management Act and Crimes Act after the Rena crashed on the Astrolabe Reef on October 5 last year.

During their sentencing in the Tauranga District Court, Judge Robert Wolff said there were "systematic failures" in the ship's navigation which was the captain's responsibility.

Balomaga was obsessed with arriving in Tauranga by 3am that day, and "put in train an unfortunate series of events that ultimately resulted in the accident," he said.

"In short the quality of navigation was such that you didn't have an accurate idea of precisely where you were. Your vessel did not have the appropriate charts that it ought to have had.

"After the collision you altered documents in order to obfuscate and cover up the reason the vessel collided with the reef."

Wolff also said Relon's decisions "ultimately" caused the Rena disaster, resulting in about 350 tonnes of oil being spewed into the sea.

However, the navigation officer had showed "true and genuine remorse", he said.

Hundreds of containers have been lifted from the Rena since it grounded, and salvors were now focusing on removing the wreck from the water.

- © Fairfax NZ News