Rio Haryanto looks set to find himself in a race against time even before he gets to make his F1 debut as the Manor team gears up to finalise its 2016 driver pairing.

The backmarker, which enters 2016 under new management and with Mercedes engines replacing its previous Ferrari units, is the last to confirm its line-up, with both seats still up for grabs - and plenty of names being linked to them.

Haryanto, who finished fourth in last year's GP2 Series standings with three race wins to his name, is listed along with Manor's 2015 drivers - Alexander Rossi, Will Stevens and Roberto Merhi - as well as Mercedes prot?g? Pascal Wehrlein as a contender for a race seat, but needs to bring sponsorship to the Banbury-based squad.

And that is where the Indonesian's quandary appears to lie as, despite speculation that he has landed the backing of the country's Ministry of Youth and Sport, he still needs to complete the rumoured EUR15m budget required to guarantee his place on the grid. Haryanto's long-term supporter, state oil company Pertamina, has already added to the sum allegedly provided by the Ministry of Youth and Sport, but rumours suggest the driver remains as much as EUR4m short of the required amount.

These claims, however, conflict with stories circulating at the end of last season which suggested that Haryanto's budget had been covered by the combination of Pertamina and the Indonesian government. The Jakarta Post, meanwhile, most recently reported that Haryanto had collected EUR5.1m from Pertamina, with another EUR6.6m from the Ministry of Youth and Sport, while other stories insist that the government had agreed to cover the shortfall, taking its contribution close to EUR10m.

"This week will be critical for Rio's hopes of entering F1," Youth and Sports Ministry spokesman Gatot S. Dewa Broto confirmed at a press conference this week, indicating that a down payment to Manor was imminent, before Haryanto could complete his budget in instalments through the year, "We've done our best, and we'll all see how it ends."

The 24-year old Haryanto has held links with Manor since its original days as Virgin Racing, testing with the team at the end of 2010, and then enjoying two further outings with the rebranded Marussia squad in 2012.