Poland fans expect a win against Group C outsiders Northern Ireland in their Euro 2016 opener on Sunday but coach Adam Nawalka warned against complacency.

"We are taking Northern Ireland seriously, they are a tough team, difficult to beat, no game at the European Championships is easy," he told reporters at the 34,500-seater Stadium Nice on Saturday.

The 58-year-old, who was part of Poland's 1978 World Cup squad as a player, said the country, and the team, have "high hopes and expectations".

With a nod to the loss of two recent friendlies, he said (Polish Football Association president) Zbigniew Boniek told the squad not to put pressure on themselves.

"So we decided not to win our last two friendly games!" he joked.

But the players are aware of the importance of the first match and the magnitude of the tournament, he said.

"I'm not worried at all, I trust in this team".

With Bayern Munich striker Robert Lewandowski spearheading the side, the 'Bialo-Czerwoni' (White and Reds) are fancied by many to reach the last 16 at least.

Extra firepower upfront is supplied by Arkadiusz Milik (Ajax), while midfielders Lukasz Piszczek (Borussia Dortmund), Grzegorz Krychowiak (Sevilla) have both enjoyed good seasons.

Despite the wealth of talent, Krychowiak, a pivotal part of the Spanish side's Europa League title win last month, said the team spirit is its biggest strength.

"That we are here in France at all is thanks to the team spirit, if there is one player who thinks otherwise then we will going back to Poland after three games," said Krychowiak.

That spirit was notably absent during the last two European Championships in 2008 and 2012 -- which they co-hosted with Ukraine -- limping out bottom of the group on both occasions.

Krychowiak was recently called Poland's "midfield general" by 1970s great Wodzimierz Lubanski.

"It is nice to hear those words from such a great player, but if we want a good result tomorrow we all need to be generals starting from the goalkeeper through to the strikers," Krychowiak said.

Marshalling the defence at centre-back is Torino captain Kamil Glik who conceded that Poland's dismal record at European championships is a record the team is desperate to set straight.

"We don't have a good history," Glik said.

Although Rennes winger Kamil Goricki is doubtful for the game with an ankle strain, Poland are brimming with confidence after a qualification campaign that saw 55 goals scored, including 13 from Lewandowski.

"We qualified in good style, the team has been developing quickly, showing progress," said Nadalka.

Poland claimed an historic first win over neighbours Germany -- who they meet at the Stade de France on June 16 -- at the 19th attempt when they stunned the world champions with a 2-0 win in Warsaw with goals by Milik and Sebastian Mila in a Euro 2016 qualifier in 2014.

The Germans gained revenge in Frankfurt last September with a 3-1 win, teeing up a spicy tie when Poland face Germany again.

"The campaign earned us respect in Poland and through Europe," said Krychowiak.

"We want to bring that level of football into the tournament," he added, cautioning that the team must keep looking forward.

"We start the clock again, now we can write history and do something amazing and that's the only thing that matters".