Contract talks between the Brisbane Broncos and star fullback Reece Walsh have reportedly been delayed as he remains one of next year's biggest free agents.

At the end of March, reports from News Corp emerged that Walsh had agreed to a new deal with the club worth $5.5 million over five seasons.

However, the superstar fullback has yet to sign the contract, and he even took to social media at the time to admit that no deal had been signed.

A key retention target for the Red Hill outfit and one of the most marketable stars in the NRL, the Broncos are now set to be offering him close to $7 million over five seasons, per The Daily Telegraph - this would be a $1.5 million increase.

Set to earn around $1.4 million a season, it would make him the same pay level as Nathan Cleary (Penrith Panthers) and Kalyn Ponga (Newcastle Knights).

It is understood that the delay has caused some worry among club officials as he will be free to negotiate with rival clubs from November 1 and is likely to catch the attention of all 16 rival NRL teams.

“We're doing everything we can to retain Reece,” Broncos Chief Executive Dave Donaghy told the publication.

Walsh re-signing will likely leave the Broncos with some tough questions around the remainder of their roster, especially in regards to centres Kotoni Staggs and Selwyn Cobbo, both of whom have been linked with rival clubs.

Although the off-season departures of Herbie Farnworth (The Dolphins), Thomas Flegler (The Dolphins), Keenan Palasia (Gold Coast Titans) and Kurt Capewell (New Zealand Warriors) have helped to ease some of the strain.