(Adds details of bid, prior bids and background) Aug 23...

(Adds details of bid, prior bids and background)

Aug 23 (Reuters) - Australian fuel supplier Ampol Ltd (ALD) has made a NZ$1.97 billion ($1.34 billion) takeover bid for New Zealand peer Z Energy (ZEL) , valuing it at a 24% premium to its last closing price, the companies said on Monday.

Z Energy said it will open its books to Ampol following the NZ$3.78 a share buyout offer, which it said followed three previous approaches that were not publicly disclosed.

Shares of Z Energy soared over 17% on news of the bid to NZ$3.58, their highest since March 2020.

The company said Ampol made at least three prior bids ranging from NZ$3.35 to NZ$3.60, verbally and through letters. Ampol said separately it made a first approach on June 2 and acknowledged a second at NZ$3.50 on July 1.

Ampol will now have four weeks of exclusive access to Z Energy's books to conduct due diligence, the two companies said.

The two companies are also talking about an option for a partial share consolidation for Ampol and potentially a secondary listing in New Zealand, Z Energy said.

Z Energy was formed when Infratil Ltd (IFT) and a local pension fund bought Royal Dutch Shell's RDSa.L downstream business in the country in 2010. In 2016, the company expanded further by buying Chevron's CVX.N local assets.

($1 = 1.4650 New Zealand dollars)