PORT Adelaide coach Matthew Primus says the AFL cannot afford to abandon the salary cap as it enters an era of free agency, claiming that financially struggling clubs won't be able to compete.

Primus spoke of the dangers uncapped free agency presented in the lead-up to the Power's NAB Cup triple-header on Sunday against Adelaide and Carlton.

"There has to be a salary cap, no doubt about it," Primus said.

"It would make life too difficult (without it)."

Cashed-up clubs stand to win when free agency is introduced from 2013, with a host of the game's stars up for grabs.

The likes of St Kilda's Leigh Montagna and Brendon Goddard, Richmond's Brett Delidio and West Coast's Quinten Lynch will all attract close attention from rival clubs, but only if the price is right.

"We're doing some good things off the field to slowly increase our financial stability but we're a fair way behind some other clubs," Primus said.

"That doesn't mean you can't win and prosper on the field, but I think a salary cap is paramount to making sure this competition stays the way it is."

If the Power can't match the financial offers other clubs are bound to make, Primus said his club needed to find other ways to promote itself - crucially, on-field success. 

"All players want to play footy and they want to win," Primus said.

"If we can start improving our position on the ladder that will make us more attractive to players to come back here.

"We have to back our culture and football club in that our players will want to stay here, play out their career here."

Despite his concerns surrounding free agency, Primus was adamant the Power would play a part in the concept to shore up their playing list.

"We have to worry about the players we have here, but we'll also target the players who we think are coming into free agency and who will complement us."

Harry Thring covers Port Adelaide news for AFL.com.au. Follow him on Twitter: @AFL_Harry