Previously hidden evidence from a plane crash in which Poland's president and 95 others died in 2010 will be revealed soon, the country's defence minister has said.

The site of the Polish presidential plane crash in 2010. Photo: Wikimedia Commons

Speaking to Polish news agency PAP, Defence Minister Antoni Macierewicz said a “subcommission” investigating the disaster would reveal its findings soon.

He added that most of the evidence was known previously but had not been revealed and that some new information would also be released.

Macierewicz earlier said that evidence of Russian involvement in the disaster had been found, but declined to give details to the news agency.

“I would gladly show you the material today, but I am not the Committee for Investigation of National Aviation Accidents,” Macierewicz told PAP.

“Allow the commission to do it at a time it sees is fit, which is not far off,” he added in the interview.

Macierewicz told PAP that the material included analyses that “build on” evidence collected since the 10 April, 2010 disaster in Smoleńsk, in western Russia.

The defence minister said a lot of information had been hidden by a commission probing the disaster under Poland's previous government from 2010-2011.

A new probe into the plane crash was launched after the Law and Justice (PiS) party came to power in Poland in late 2015. PiS politicians have challenged a report under the previous Polish government which concluded the crash was an accident.

But a so-called Macierewicz committee in 2014 found that the presidential plane was brought down by an explosion.

The crash in western Russia on 10 April, 2010 saw the death of 96 people, including then-President Lech Kaczyński – twin brother of PiS's current leader Jarosław Kaczyński – and then-first lady, as well as many top military and government officials.

The Polish report on the causes of the tragedy, which happened in dense fog on approach to a military airfield lacking ground identification radar, cited a catalogue of errors on the Polish side, while also pointing to errors made by Russian staff at the control tower of the Smolensk military airport. The Russian report placed all the blame on the Poles. (vb)