Z Energy's board of directors has unanimously recommended shareholders accept a marginally improved takeover offer from Australian fuel retailer Ampol. 

After six weeks of exclusive takeover negotiations, the two companies announced a binding scheme of arrangement under which Z shareholders would receive $3.78 per share and at least a 5c interim dividend, probably in November. 

The deal values Z Energy at around $2 billion. 

If the sale is not completed by the end of March, the cash being offered will increase by up to 10c per share. 

"The Z Board unanimously recommends that shareholders vote in favour of the Scheme, subject to the Scheme consideration being within or above the valuation range specified by the independent advisor and in the absence of a Superior Proposal being made for Z (as defined in the transaction agreement)," Z Energy said in a statement on Monday morning. 

The offer still faces a number of regulatory hurdles, with the approval of both the Commerce Commission and Overseas Investment Office required. 

It is also conditional on the transition of the Marsden Point fuel refinery to an import only terminal and approval from both Z Energy's shareholders and the High Court. 

A joint statement said the deal is expected to be completed in the first half of 2022. The two companies have agreed a $20 million break fee payable "in certain circumstances" including if regulatory approach is not obtained within 12 months and the scheme is terminated. 

Ampol is the owner of the Gull petrol stations. Monday's announcement saw Ampol committed to selling the business as part of its attempts to gain competition approval to buy Z Energy. There was speculation in the Australian on Monday that it may look to float Gull. 

Ampol also reaffirmed its plans to seek a secondary listing for its shares on the NZX. 

In August, Z Energy announced it had received a series of unsolicited offers from Ampol. While it did not initially recommend the indicative $3.78 approach announced in August 23, it revealed the deal to seek feedback from shareholders. 

While analysts speculated that the Ampol offer may flush out other bidders, none appear to have come forward. 

"The Z Board believes that the scheme represents fair value for Z shareholders," Z Energy chair Abby Foote said. 

"The board is also satisfied that Ampol will continue to invest in New Zealand's energy transition towards a low carbon future and its scale will deliver advantages for the fuel industry in New Zealand."