Woodside Petroleum Ltd has agreed a $1.25 billion deal to acquire a 30 percent stake in Leviathan, a natural gas find off Israel's Mediterranean shores, as Australia's biggest oil and gas company expands its reach outside its home market.

Woodside said on Monday it will be the operator of any liquefied natural gas (LNG) development of the field, which is estimated to contain around 17 trillion cubic feet of recoverable natural gas. Noble Energy Inc will be the upstream operator.

The Australian firm has been building a bigger international presence to offset a jump in costs at domestic oil and gas developments, with Woodside's own flagship LNG project coming in $940 million over budget.

Woodside announced in October it had agreed to explore for oil and gas in Myanmar with South Korea's Daewoo International Corp.

In May, Woodside was one of 15 companies, including majors such as Total, to bid on nine offshore gas blocks in Cyprus.

Woodside CEO Peter Coleman said the Leviathan deal was a significant step towards realising Woodside's ambition to secure world-class growth opportunities.

Texas-based Noble Energy has a 39.66 percent share in the field. Israel's Delek Group, through subsidiaries Delek Drilling and Avner Oil Exploration , has a 45.34 percent stake. Ratio Oil Exploration holds the remaining 15 percent.

The agreement also allows Woodside to participate in further exploration opportunities in the 349-Rachel and 350-Amit Israeli offshore petroleum licences.

"Acquiring an interest in these permits is an exciting opportunity to grow our portfolio in the emerging Eastern Mediterranean basin," Coleman said in a statement.

Woodside said the agreement involves an initial upfront payment of $696 million, a further payment of $200 million once laws permitting LNG export are in force and a $350 million payment on a final investment decision in relation to an LNG development.

It is also subject to potential annual LNG revenue sharing payments equal to 11.5 percent of Woodside's incremental revenue above an agreed escalating price threshold over the life of the project, capped at $1 billion.

Shares in Woodside were up 0.7 percent at A$34.04 ($35.51) at 1213 GMT, in line with a firmer broader market. ($1 = 0.9585 Australian dollars)