(Updates with more details on the offer, background) March 24...

(Updates with more details on the offer, background)

March 24 (Reuters) - Private equity firm Potentia Capital raised its takeover offer for Nitro Software Ltd (NTO) on Friday, saying it now has relevant interests in more than 75% of the Australian software maker shares, a pre-requisite for the higher bid.

Potentia raised its buyout offer to A$2.20 per share from A$2.17, valuing Nitro at A$541.9 million ($362 million).

Earlier this month, Potentia outbid KKR Inc KKR.N -backed Alludo's A$2.15 per-share offer, winning a takeover battle that started last October.

Potentia had said, at the time, its offer could go to as high as A$2.25 per share if it got a 75% stake in Nitro by March-end and if at least 25% of total Nitro shareholders accepted a scrip offer.

($1 = 1.4968 Australian dollars)