Sydney chairman Scott Barlow said Del Piero had rejected other offers to move to Australia.
Sydney: Sydney FC announced Friday that former Juventus forward Alessandro Del Piero had agreed to contract terms with the A-League club, but the player's brother and agent said the deal was not finalized.
The 37-year-old Italian had been in talks with several clubs but Sydney chairman Scott Barlow said Del Piero, who played a record 513 matches for the Serie A team and 91 times for Italy, had rejected other offers to move to Australia.
Barlow said "this is huge for Sydney FC, huge for the A-League and huge for Australian football."
Sydney FC chief executive Tony Pignata will travel to Italy to finalize the deal with Del Piero, a member of Italy's 2006 World Cup-winning team.
"I can confirm the negotiations. We are seriously examining the offer from Sydney, but there is no deal and it's not accurate to say that it will be signed Monday," Del Piero's brother and agent, Stefano, told Italy's ANSA news agency.
"You can't expect to close a deal by long-distance," Stefano Del Piero added. "If we're able to develop all the aspects (of the deal), then Alessandro can say, 'I'll think about it and decide.' It's the same thing we've done with, for example, (Swiss club FC) Sion, which we've met with twice."
Juventus announced early last season that they would not renew Del Piero's contract and he has been linked with moves to the Middle East, China, Argentina, the United States and Switzerland.
Contract terms were not released by Sydney FC, but Australian media this week reported that Del Piero was offered about $2 million a year, which would make him the highest-paid athlete in Australia's four football codes, which also include rugby league, rugby union and Australian Rules football.
The A-League, which has had several teams fold in the last two years due to financial problems and dwindling attendances, needs Del Piero as a high-profile drawcard.
Its other past marquee signings have been formerly England-based Trinidad and Tobago star Dwight Yorke, who also played for Sydney in 2005-06, and former Liverpool forward Robbie Fowler, who played with the now-defunct North Queensland team and Perth Glory from 2009-11.