A permanent transfer move for Paulo Bernardo to join Celtic has hit a 'stumbling block', according to a report.

The midfielder spent last season on loan at Celtic from Benfica and speculation has ramped up over a return to Parkhead on a full-time basis.

A clause in Bernardo's loan deal meant Celtic held an option to buy the player but reports have suggested club chiefs are keen to negotiate a lesser fee.

Now, reports in Bernardo's homeland suggest a transfer fee won't prevent a deal - rather the player's salary could emerge as an issue.

Record claim the player's salary could make a permanent deal "difficult" despite a desire from Celtic to sign the midfielder.

It's reported Bernardo's wages at Benfica could be tough to match due to his deal being signed when he was 18 and viewed as a star of the future.

READ MORE: Celtic transfer news and rumours before the transfer window

Since then, Bernardo has been deemed surplus to requirements in the Benfica first team and available to make an exit this summer.

The 22-year-old previously hinted he would be interested in an extended stay in Glasgow.

He said: "The manager and I just want to keep things going well and to improve a lot.

"I am enjoying it a lot. The fans are unbelievable and they like me, so I am feeling good too. I just have to keep going."