China's "one country, two systems" principle has brought laudable achievements in economic and social development to Macao over the past 20 years, said Portuguese Prime Minister Antonio Costa.

"We value the 'one country, two systems' principle," Costa said in a written statement sent to the country's Lusa News Agency on the occasion of the 20th anniversary of the return of Macao to the motherland.

"The principle has allowed Macao and the Macao people to enjoy material and social development, which deserves our appreciation, and has contributed to the maintenance of Macao's specificities," he said.

Economic development "has allowed Macao to maintain its own lifestyle and identity and a close connection with our country", he said.

Costa also praised Macao for its important role in promoting the development of Portugal-China relations.