"This basin (the Gulf) we all share. Talk of closing the Strait of Hormuz has a great impact on us," official news agency KUNA quoted Foreign Affairs Minister Sheikh Mohammad al-Salem al-Sabah as saying in a television interview.
KUNA quoted him as saying Kuwait would not allow the United States to launch an attack on Iran from its soil.
About 40 percent of global oil exports leave the Gulf via the Strait of Hormuz, off Iran's southern coast. Tehran has said it will impose shipping controls there if it is attacked, and has warned Gulf neighbours of reprisals should they take part in any attack.
"Merely talking about such a closure (of the Strait of Hormuz) creates a state of tension and will raise the insurance costs on vessels passing through," Sheik Mohammad said.
"We are now paying additional amounts for shipping due to a statement, which may be a test balloon or war of words … therefore cautious and calculated words are desired."
The United States has refused to rule out military action against Iran if Tehran continues with attempts to enrich uranium. Tehran says it wants to develop nuclear power, while Washington says Iran wants atomic arms.
An air force drill staged by Israel in June sparked speculation about an assault on nuclear sites in Iran, which has vowed retaliatory strikes at Israel as well as U.S. interests and military bases and shipping if it is attacked.
"It is true that we are allies of America … (but) we are against escalation against Iran," Sheikh Mohammad said. "We have the courage to correspond with our main allies for what we see as in the interest of Kuwait and the region."
Tiny Kuwait, home to about one-tenth of global oil reserves, has relied mainly on the United States for its security since 1991's U.S.-led Gulf War ended Iraq's seven-month occupation.
Sheikh Mohammad said Kuwait and other Gulf Arabs supported Iran's right to acquire nuclear energy for peaceful purposes, but added: "Our friends in Iran should know that not responding to decisions of the international community will not bring benefit to them, or to their friends who support their right."
Britain, France, Germany and the United States are considering imposing additional sanctions on Iran over its nuclear work, a senior British official said on Friday. (Reporting by Rania El Gamal; Editing by Inal Ersan and Catherine Evans)
