The Rugby Football League has sent a letter of protest to Sport England over alleged moves by the Rugby Football Union.
Jason Robinson has enjoyed great success after he switched codes last year and reports have suggested that some other top league players are being targeted for the 15-man game.
RFL director of rugby Greg McCallum has written to Derek Casey, chief executive of the government sports funding agency, highlighting alleged approaches to players and officials who are registered with the RFL.
"There seems to be no morality to the approaches by the RFU and would seem to us to be an attempt to stem their reported increasing player losses by picking up ready-made potential stars and star makers from rugby league," said McCallum.
"We have become increasingly aware that besides targeting existing top-class rugby league players, the RFU have been approaching both up-and-coming rugby league stars, who have been identified within our world-class plan, and also making overtures to our development officers.
It has also been suggested England union manager Clive Woodward is considering packing his team with league players to counter a possible mass boycott of his team, whose members signed contracts tying them to their clubs for the next 10 years.