The Netherlands Sports Council has revealed Zandvoort is the only circuit still in contention to host Formula 1 and revive the Dutch Grand Prix, with a deadline set for the end of March to decide on its future.

Momentum has built in recent years for F1 to return to the Netherlands for the first time since 1985 following the success of Dutch youngster Max Verstappen, leading to a number of possibilities being considered.

Zandvoort and Assen have been the two leading circuits in contention to host F1, but it has been revealed in an open letter issued by the Netherland Sports Council (NLsportraad) that only Zandvoort remains a viable option.

The letter confirms Zandvoort signed a letter of intent to host the Dutch Grand Prix on December 13, but was informed by the Dutch government that it would not subsidise the race's funding, leaving it dependent on sponsorship and private investment. A "hard deadline" to decide on the future of the race has been set for March 31.

"Circuit Zandvoort explained that there are sponsor partners that are interested but their confidence in the business case of Zandvoort might have decreased because the central government chose to only facilitate the plans and not provide subsidy," the letter reads.

"This explanation is consistent with the findings of the NLsportraad that the confidence of companies increases when the central government is willing to facilitate and invest. Sport events flourish with public-private partnerships.

"Furthermore the management of circuit Zandvoort noticed that potential sponsors are becoming increasingly wary because of messages in the media about the (alleged) competition between circuit Zandvoort and circuit Assen."

While NLsportraad found that Assen claimed it had a "foreign investor" that could cover some of the costs and already had infrastructure in place, after contact with F1 management, it was explained that Zandvoort was the only track deemed viable to stage F1.

"Direct contact between the NLsportraad and the responsible manager of FOM made it clear that circuit Zandvoort is the only candidate in the Netherlands suitable to organize a Formula 1 race in the Netherlands because of the history and the close proximity of big cities and airports," the letter reads.

"FOM stated that the only possibility of the Formula 1 race being awarded to the Netherlands is if the business case of Zandvoort is completed in time to the deadlines discussed."

The NLsportraad offered its support to Zandvoort's push to find the required partners in time for the deadline to be met, and stressed the need for the various stakeholders and bodies to work together.

"The NLsportraad sincerely hopes that Circuit Zandvoort is able to partner with (Dutch) companies for sponsorship at such short notice. The NLsportraad appeals to the national government, provinces and cities to discuss the ways in which the organization of this event can be supported and used in such a way that the social returns are optimised.

"The NLsportraad is of the opinion that organizing a Formula 1 race provides a unique opportunity for many Dutch sport fans to enjoy motorsports and their hero Max Verstappen. If utilised well, the Formula 1 race also offers opportunities to develop the region and to promote the Netherlands in many different ways.

"Cooperation is crucial: cooperation between private and public parties, cooperation within the public sector and cooperation between government departments."