(Reuters) - Australian diversified investor Seven Group Holdings made an offer on Monday to take full control of Boral, valuing the remaining about 28% stake it does not already own in the building materials maker at A$1.9 billion ($1.24 billion).

Seven Group (SGH) currently owns a 71.6% stake in Boral. Under the offer, Seven Group will offer a minimum of A$6.05 per share in cash and scrip to Boral shareholders, valuing the company at A$6.67 billion ($4.35 billion).

The minimum offer represents a 3.4% premium to Boral's last closing level of A$5.850.

"By acquiring the Boral shares it does not already own, SGH intends to drive an acceleration of Boral's performance journey and long-term growth," Seven Group said in a statement.

"The integration of Boral into SGH is consistent with the group's owner-operator strategy and would increase SGH's strategic flexibility and access to Boral's cash flow."

Boral in a separate statement recommended its shareholders take no action on the takeover offer, adding that an independent board committee had been established to review the offer.

Seven Group in 2021 made multiple takeover offers to acquire Boral, which it kept rejecting citing undervaluation of its business.

Seven Group ended up amassing around a 71% stake in just a few months in 2021 as record low interest rates boosted Boral's domestic business, generating buyer interest.

Seven Group on Monday added it will raise its offer for Boral by another 10 Australian cents in the event it achieves an aggregate 80% stake in Boral or if Boral's board unanimously recommends the offer to its shareholders, or both.

The offer would increase by another 10 cents if Seven Group's stake reaches 90.6%, the compulsory acquisition threshold.

However, Seven Group clarified it would not buy Boral shares for an amount above A$6.25 apiece for at least a year after the offer close.

($1 = 1.5321 Australian dollars)

(Reporting by Sameer Manekar in Bengaluru; Editing by Lisa Shumaker and Chris Reese)