The two allies are yet to firm up the arrangement for the October 21 polls and the reason cited is the ongoing 'Pitrapaksh', a fortnight-long period considered inauspicious by Hindus.
The eagerly-watched and anticipated tie-up between the BJP and Shiv Sena has apparently hit a roadblock, with the latter insisting on a 50:50 seat-sharing formula and rotating the CM's post, which is not acceptable to the former.
Reflecting the trouble being encountered, a harried MP of Shiv Sena Sanjay Raut has compared the situation to India's partition of 1947, saying it is more difficult than even that episode.
The Sena is worried that if the alliance isn't finalised soon, around a dozen sitting legislators, including some ministers, may ditch it for the BJP.
BJP President Amit Shah was likely to visit Mumbai today but seems to have deferred it to after the end of 'Pitrupaksh' on Saturday. The political action in the alliance is expected to gain momentum thereafter.
In the meantime, to show everything is hunky-dory, Chief Minister Devendra Fadnavis and Shiv Sena President Uddhav Thackeray have met or shared the stage on a couple of occasions in the recent days.
Despite the official display of camaraderie, the Sena, which won 63 seats in the 2014 Assembly elections, is demanding 135 seats. However, the BJP, which bagged 122 seats last time, is reportedly ready to part with around 110-115 seats only in the 288-member state assembly.
Thackeray reiterated last week that as per the earlier commitment, the two parties would contest the elections with 135 seats each and share the post of CM for 30 months each.
The BJP also has to contend with demands from the smaller BJP allies like Union Minister Ramdas Athawale's Republican Party of India (A) for 10 seats and others for suitable representation.
BJP and Shiv Sena, which formed a coalition government in the state in 2014, were loggerheads till just before the Lok Sabha elections held in April-May this year.
Shiv Sena, particularly, was very angry with the Modi government at the Centre for more than 4 years even as it was a part of it.
Led by Uddhav Thackeray, the party leaders would lash out at the central government, along with the Fadnavis government, almost on all issues.
The party had declared a number of times that it would contest the Lok Sabha elections as well as the Maharashtra Assembly polls separately. In fact, the two parties contested the Lok Sabha by polls in Maharashtra in May last year against each other. The by election in Palghar was won by the BJP, defeating the Shiv Sena.
However, the anger disappeared just ahead of the Lok Sabha elections and the two parties decided to context the polls jointly in the state where 48 seats were at stake.
The BJP contested at 25 seats, while the Shiv Sena fought at 23 seats and the combine had a landslide win with 41 seats.
For the upcoming Assembly elections too, the two parties need to sort out their differences in time, if they have to contest jointly.
( With inputs from IANS )