Former Penrith five-eighth Harry Siejka will honour the memory of his grandfather - who came to Australia after being forced to work in German labour camps during World War II - when he plays for Poland at the Emerging Nations World Championship.

Seijka, who this year played for Dapto in the Illawarra competition, will line-up alongside brother Liam in the Poland team to meet Hong Kong at St Marys League Stadium on Thursday.

The 26-year-old is eligible to represent Poland through his late grandfather, who was taken to work for the Nazis in Germany as a teenager after the family's farm was confiscated by Hitler's regime.

"My grandfather was a prisoner of war when Hitler took over Poland," Siejka said. "They took the property, I think they used it to store stuff and once the war was finished it was burned down.

"My pop was only 16 at the time. He had two brothers and when they took them from the farm, they were sent to Germany to work on different farms.

"My pop died when I was younger but just speaking to my nan, some of the stuff he went through was just crazy.

Harry Siejka during his time playing for the Penrith Panthers. ©NRL Photos

"Once the war had finished he just wanted to get as far away as possible so he came to Australia. He didn't know anyone here all he had was a suitcase so he went to Bathurst and stayed in a migrant camp there."

Siejka has previously played for Poland at the Cabramatta Nines but the match against Hong Kong will be his first Test for the fledgling league nation, which has a six-team competition.

Poland play Japan at New Era Stadium at Cabramatta on Sunday and Siejka is hopeful they can make it to their play-off stage of the tournament, which features 11 countries and four regional confederation teams.

"For anyone with a bit of heritage it is an honour to put on a Poland jersey and represent your family," he said.

"I think if you asked someone three months ago, no one would have known Poland played rugby league, but this is just the start.

"In Super League I remember playing with three or four blokes who were Polish so if it did get a bit of exposure I think you'd get a lot of players come out of the woodwork and throw their hand up for it."

Jayden Watene-Zelezniak, the younger brother of Dallin and Malakai, is also in the Poland squad, while Euan Aitken, Christian Welch, Matt Srama and Luke Srama are among the current or former NRL players believed to be eligible for Poland.