Nov 18 (Reuters) - Australia's Nitro Software Ltd said on Friday it would not allow its largest shareholder and suitor Potentia Capital access to its books without making a superior bid that could trump an offer made by KKR Inc's Alludo.

The software provider earlier this week determined the near A$500 million ($335 million) offer from Alludo, of A$2.00 per share, to be superior to the $A1.80 takeover offer made by Potentia.

In a letter to the Australian Securities Exchange on Friday, Potentia, which holds 19.8% of Nitro, said it wanted to carry out due diligence on potentially increasing its offer.

Potentia did not table a higher offer but said it hoped it could "meet or exceed" Alludo's bid after examining Nitro's accounts.

It said it could offer Nitro shareholders shares in a public company that would form part of its bidding group, without identifying the firm.

Nitro said Potentia had been offered an opportunity for due diligence in October alongside other parties like Alludo.

"Potentia declined to sign up to a non-disclosure agreement, which contained customary terms that were agreed to by other interested third parties," Nitro said.

Nitro shares were trading at $A2.10 on Friday but remain down 15% so far in 2022. (Reporting by Roushni Nair in Bengaluru; Editing by Shailesh Kuber and Cynthia Osterman)