* Zhaojin sweetens offer price to A$0.68 from A$0.58

* Zhaojin confirms approvals from Chinese regulatory

April 15 (Reuters) - China's Zhaojin Mining said on Monday it is raising its offer to buy the shares it does not already own in Tietto Minerals to up to A$733 million ($474 million), sending the Australian gold explorer's shares to a one-year high.

Last October, Zhaojin had placed a bid for Tietto Minerals, which owns its flagship Abujar gold mine in Côte d'Ivoire, for about A$629 million.

Shares of the Perth-headquartered firm rose as much as 3.1% to A$0.670 following the announcement, hitting their highest level since April 19, 2023.

Tietto in November, however, said the offer "materially undervalued" the company, stating that it was "opportunistically timed" by Zhaojin as it came after an improvement in the Abujar gold mine.

The Chinese gold miner said on Monday it will sweeten its offer for the Australian explorer to A$0.68 apiece from A$0.58. The increased offer price represents a 60% premium to Tietto's last closing price on Oct. 27, before the initial offer was tabled.

The offer by Zhaojin, which already owns a 7.02% stake in Tietto, values the latter at A$768.3 million.

The company also confirmed that its unit, Zhaojin Capital, has received all of the Chinese regulatory approvals related to the deal, including approvals from the NDRC, among other regulatory bodies.

The acquisition would help expand business overseas and boost profitability, the Chinese gold miner said in its takeover offer statement in October 2023.

Subject to deal completion, Zhaojin says it will support the development of Tietto's Abujar gold mine and exploration activities in West Africa.

($1 = 1.5458 Australian dollars) (Reporting by Shivangi Lahiri in Bengaluru; Editing by Leslie Adler, Diane Craft and Sherry Jacob-Phillips)