The BJP and its ally, the Haryana Janhit Congress of Kuldeep Bishnoi are expected to win five of the state's 10 parliamentary seats.
The Congress will win three seats, the poll shows. The party has been pilloried for alleged sweetheart land deals in the state, involving Robert Vadra, the son-in-law of Congress president Sonia Gandhi.
This marks a change from the previous opinion poll, which had predicted that the BJP and its ally will win seven seats. Since then, it appears to have ceded some ground to Om Prakash Chautala of the Indian National Lok Dal (INLD).
The INLD has said it will support Narendra Modi, the BJP's prime ministerial candidate, should he fail to win a majority. The INLD and BJP had snapped ties in just before the last state election in 2009.