The joint pledge came after DISY head Nicos Anastassiades met Turkish Foreign Minister Abdullah Gul and other senior Justice and Development Party (AKP) officials during a rare visit to Ankara.
"In our talks, we decided to increase relations between our parties. Our target is a solution on Cyprus," Anastassiades said on Thursday.
The DISY leader – the first Greek Cypriot political leader to visit Turkey since Cyprus' partition in 1974 – described his meeting with Gul as "useful" and said they had discussed a failed UN plan to re-unify the island last year.
The UN plan failed when Greek Cypriots rejected it with an overwhelming majority in a referendum on 24 April, even though Turkish Cypriots gave it a strong support.
Anastassiades is the first Greek
Cypriot leader to visit Turkey
The outcome ensured that only the internationally-recognised Greek Cypriot sector joined the European Union on 1 May while the breakaway Turkish Cypriots were left out.
DISY was the only major Greek Cypriot political force to rally behind the UN scheme, which was also supported by Ankara.
AKP deputy chairman Saban Icli described Anastassiades' visit as "courageous" and did not rule out AKP officials visiting Greek Cyprus for talks with DISY leaders.
Cyprus has been divided along ethnic lines since 1974 when Turkey occupied its northern third in the wake of an Athens-engineered coup aimed at uniting the island with Greece.
Turkey still maintains some 30,000 troops in the breakaway Turkish Cyprus in the north and refuses to endorse the internationally-recognised Greek Cypriot government in the south.
The two sides have no diplomatic ties.