Swansea are expected to bring in a number of further recruits - but Duff says transfer funds will not be wasted.

"We do need to add, there's no doubt," Duff said.

"Is there money available? Yeah, but we don't throw it away like confetti because it's burning a hole in your pocket.

"At Cheltenham Town I spent £5,000 in four years. At Barnsley we sold £5m worth of players last year and spent £100,000 and we still had success. So you don't have to always spend money."

Swansea's squad was thin in certain areas last season, particularly after a January window in which six players left and none came in.

They have lost defensive regulars Ryan Manning and Joel Latibeaudiere this summer, while Luke Cundle and Matty Sorinola have left the Welsh club after loan spells.

It could be that there are further departures to come, with major doubts over Joel Piroe's Swansea future amid links with the likes of Everton, Leicester City and Southampton, as well as clubs in Serie A.

Duff says the question of how many signings are required is "a difficult one to answer" at this stage.

"It's getting good players in the building, as many as we can, without bankrupting the club," he said.

"I am under no illusions that there's going to be an open cheque book.

"We have to do it diligently and get the right player and character to complement what we have got."

Piroe, 23, has been a hit since joining Swansea from PSV Eindhoven two years ago in a deal worth £1m rising to £2m.

Swansea can expect to make a sizeable profit on Piroe should he depart this summer, though their hand is weakened because the Dutch striker only has a year to run on his contract.

"I have plans for every scenario," said Duff.

"I had a good conversation with Joel. He was asking about detail in terms of what I want from him.

"Until anything changes, we'll keep doing it. If he goes, he goes, if he stays, he stays. It's nothing personal, it's football."

Andy Coleman has said he will have the final say on all major decisions at the club having been named Swansea chairman in May.

However, he says he will rely on Duff and new sporting director Paul Watson when it comes to transfers.

"Those decisions are going to be made by the football people," Coleman said.

"It's an operating business so we all have to keep that in mind. Players come and go regardless of your table position or what league you play in."