(Adds details, background) ZAGREB, June 20 (Reuters) - Croatian...

(Adds details, background)

ZAGREB, June 20 (Reuters) - Croatian oil group INA INAI.ZA said on Wednesday it has decided to buy back a 50 percent stake held by Italy's ENI ENI.MI in a joint venture exploiting 10 gas wells in the northern Adriatic.

"The deal confirms Croatia's ambitions to increase domestic gas production," INA senior official Tvrtko Perkovic said.

The wells produce 1.5 million cubic metres of gas a day and INA aims to increase output by 400,000 cubic metres per day, Perkovic said.

The two companies signed a deal in 1996 to set up the INAgip joint venture which has the exploitation rights until 2036.

Tvrtkovic told reporters the details of the transaction are confidential.

Croatia imports more than 40 percent of its gas consumption. Its energy ministry recently said it plans to pass a new law on hydrocarbons aimed at boosting exploration, most notably in onshore areas.

The newest European Union member, Croatia aims to produce 30 percent of its oil and more than 50 percent of its gas needs domestically by 2030.

INA has a market capitalisation of 32.1 billion Croatian kuna ($5.03 billion).

In April, Croatia picked a consortium of banks to advise it in the process of buying back 49 percent of INA's shares from Hungary's MOL MOLB.BU .

Zagreb, which owns close to 45 percent of INA, and MOL, have for several years been at odds over management rights and INA's investment strategy. ($1 = 6.3817 kuna)