Tweeting from Kumar's official Twitter account on Tuesday night, she said Modi was her last hope in the case because repeated entreaties to Maharashtra Chief Minister Devendra Fadnavis had been futile.
She named builder Samir Bhojwani, who has allegedly falsely claimed ownership of two plots in Pali Hill on which Dilip Kumar's bungalow is built.
"To the honourable @PMOIndia Shri @narendramodi. Awaiting for appointment. I'm tired of repeated assurances from CM @Dev_Fadnavis "I Am Trying". Sir you are the last hope of protecting Dilip Sahab's only house from land mafia Samir Bhojwani. I beg (sic)."
Modi was in Mumbai on Tuesday for a day and met producers and actors to discuss issues related to the Hindi film industry but Saira Banu could not meet him.
She said she plans to follow up with the PM on the matter.
"I did not meet the prime minister here as he has been busy. But I have learnt that his office has asked people here to look into the matter. I have tweeted about it.
Fadnavis said on Monday that he will speak to Kumar, 96, and his family to allay their fears over the property issue involving Bhojwani.
Kumar's bungalow is located in the upscale Pali Hill area of Bandra.
In January, the Economic Offences Wing (EOW) of Mumbai Police registered a case of cheating against the builder for allegedly trying to grab the veteran actor's bungalow.
After the offence was registered, a team of EOW sleuths raided Bhojwani's residence in Bandra from where they seized weapons, including knives and daggers, officials said.
Bhojwani was arrested by EOW in April and has since been released from jail.