Dr Singh's dinner with UPA leaders comes close on the heels of his similar interactions with leaders of crucial outside supporters Samajwadi Party and Bahujan Samap Party. He hosted dinner for SP chief Mulayam Singh Yadav and his son Akhilesh last week and followed it with lunch for BSP chief Mayawati on Sunday.
The PM is reaching out to allies and outside supporters as the government faces the prospect of a motion entailing voting on FDI and even a possible threat of the no-confidence motion.
The Left parties have tabled a motion that will seek a vote on FDI. The main Opposition Bjhartiya Janata Party, its ally Janata Dal-United as also the Trinamool Congress, which parted ways with the UPA few months back on the issue, have also given notices.
Those from the opposition who have given notices include Shatabdi Roy of the Trinamool Congress, BJP's Ramesh Bais, A T Nana Patil, Hansraj Ahir and Rajiv Ranjan Singh of the JD-U.
To add to government's discomfiture, sulking ally Dravida Munnetra Kazhagam on Wednesday declined to disclose its stand on how it would vote either on such motions or the no-confidence motion, likely to be moved by Trinamool Congress.
DMK chief M Karunanidhi said in Chennai on Wednesday that his party's stand on the FDI issue is a "suspense".
Asked whether the DMK would support the Left and some other parties' proposed resolution with provision for voting in Parliament on FDI, Karunanidhi said the party's views would be made known after consultations with parliamentary party members.
The support of DMK, the second largest group in UPA with its 18 MPs in Lok Sabha, is crucial for the UPA in case of a voting on a motion.
At present, the government enjoys the support of about 265 MPs, including DMK, in a House of 545. With the support of the Samajwadi Party, 22, and BSP, 21, the backing for the ruling coalition goes a little over 300, which is comfortable over the required 273 majority mark in Lok Sabha.
The BSP and SP together or individually have not shown signs of withdrawing support so far.
BSP chief Mayawati, who has hinted at the possibility of early polls, remained vague on her party's stand on the FDI issue after her lunch with the PM on Sunday.
"Whenever such a situation crops up, ask us this question (then). Why do you want our response in advance," she said.
She noted that her party members have authorised her to take a final decision on support to the UPA but she has not taken a call on the issue so far.