Sam Tomkins.

Sam Tomkins believes the Super League suffers more than the NRL when players swap between competitions and questioned why English clubs spend up big on signing players from Australia and New Zealand.

More than a dozen NRL players have signed fresh contracts with Super League clubs for next season in comparison to the four heading the other way.

English trio John Bateman, Ryan Sutton and Ryan Hall will be joined by Man of Steel award winner Ben Barba, who is returning to Australia to play for North Queensland.

Tomkins, who gained a release two years into a three-year contract with the New Zealand Warriors in 2015 to return to England, says NRL clubs target quality than quantity with more to follow due to his nation's rise in the international ranks.

″We lose a bit when our key players go over and that affects the standard,″ Tomkins told NRL.com.

″Some of our best talent is in Australia. We've got a lot of quality still in England but if you look at the squad now, there's a lot who could go over to the NRL and play.

″And they will, there will be more players from this group that go to the NRL in future years. There's a much bigger salary cap for players to test themselves and get a financial gain.

″It's inevitable unless something changes over here.″

Tomkins is also on the move ahead of the next club season, joining Catalans Dragons. Sutton and Bateman, who also called the DW Stadium home last season, will take on the challenge of playing in the NRL at Canberra.

It's frustrating when teams spend money on overseas players that aren't really adding anything here

Sam Tomkins

Former Raiders five-eighth Blake Austin joins Konrad Hurrell, Kevin Naiqama and Akuila Uate as the headline acts to feature in the Super League from next season.

″You get some players who come in and really light up the competition which is great,″ Tomkins said.

″But we also get overseas players that come and don't do that. It's frustrating when teams spend money on overseas players that aren't really adding anything here.

″But we're lucky when we get a Ben Barba, someone who sets the place alight. In the first half of the season you couldn't touch him, he was brilliant.

″We've had some at Wigan in the past, players like Pat Richards and George Carmont. Hopefully, that continues and it's not as one-sided.″

Tomkins signed a big-money deal to link with the Warriors but was plagued with injury and homesickness before gaining an early release.

The England five-eighth goes head-to-head with former teammate Shaun Johnson at Anfield in the second Test between England and New Zealand on Sunday.

″I learnt a lot but as a side, we were just never consistent,″ Tomkins said of his time at the Warriors and overall NRL experience.

″I was in my comfort zone at Wigan, we won most of our games and were competition leaders.

″But in New Zealand, I wasn't in the best team or playing my best rugby, it matured me a little bit and I come back to the Super League a smarter player.″