Mr Sihasak said this after holding a meeting with Jesús Miguel Sanz Escorihuela to discuss the EU's statement condemning the coup in Thailand and outlining measures to pressure the National Council for Peace and Order (NCPO) to quickly restore democracy in the country.
These include the suspension of official visits to and from Thailand and the signing of the Partnership and Cooperation Agreement (PCA) between EU and its member states with the Thailand until a democratically elected government is in place.
Mr Sihasak said he expressed disappointment with the EU's decision which he said was made without taking into consideration developments being made in Thailand to ease the situation and lead the country back to democracy.
He also expressed disagreement with the EU's unilateral decision because Thailand, as a friendly country, is widely open to consultation to promote better understanding with the EU.
While Thailand understands the EU's stance, the EU should also understand the situation in Thailand, Mr Sihasak said.
He said he asked the EU to review its decision because it concerns the interests of both sides and international relations.
Mr Sihasak said the head of the EU delegation to Thailand said the measures to be taken are not sanctions against Thailand because trade, investment and tourism relations will continue as usual.
The decision has nothing to do with the process of entering into a free trade agreement (FTA) because the EU still attaches importance on Thailland and hopes Thailand will play an important role in Asean, particularly in the Asean-EU ministerial meeting scheduled for July, Mr Miguel Sanz said, according to Mr Sihasak.