GPT made a $3 billion takeover offer for two thirds of rival Australand's businesses last December, but was rebuffed.
The reaffirmation came today as GPT unveiled its surge in full year profit.
The chief executive Michael Cameron said an Australand offer was still in the works.
"We are committed to advancing a proposal that's going to be in the best interest of Australand and GPT security holders," he said.
GPT Group has gained a big uplift in profit because of a strong operational performance and an rise in underlying values.
Net profit after tax rose to $594.5 million in the full year ending December 31 from $246.2 million with Michael Cameron saying the group again exceeded expectations.
The GPT net tangible assets were up 3.9% helped by a big rise in the value of Melbourne Central in the second half.
The GPT retail portfolio has a 99.5% level of occupancy with the retail portfolio achieving comparable income growth of 3% over 2012.