UPDATE 1-Dutch state consolidates ABN AMRO stake

* ABN AMRO stake valued at 6.5 bln euros

* Transfer to boost Fortis Netherlands' solvency (Adds detail, background)

AMSTERDAM, Dec 15 (Reuters) - The Dutch government will take over Fortis Bank Netherlands's stake in ABN AMRO, a step that will simplify the structure of the state-owned businesses and improve the bank's solvency, the Dutch finance ministry said on Tuesday.

The Dutch state took over the Dutch business of Fortis, as well as ABN AMRO that was owned by the Fortis (FOR.BR) financial group, in October for 16.8 billion euros ($23 billion).

The Belgian-Dutch group was split up with BNP Paribas (BNPP.PA) buying most of the financial group's Belgian operations after an initial partial nationalisation failed to calm investor concerns.

Fortis Bank Nederland owns a stake in RFS Holdings, a holding company set up by Royal Bank of Scotland (RBS.L), Santander (SAN.MC) and Fortis to acquire ABN AMRO last year for 70 billion euros.

Transferring the stake in RFS from Fortis's Dutch banking unit to the Dutch government will have a positive effect on the bank's solvency, Dutch Finance Minister Wouter Bos wrote in a letter to parliament.

The stake in RFS Holdings, valued at 6.5 billion euros, will be subtracted from the 50 billion euros that Fortis Bank Netherlands still owes the Dutch state after it refinanced the bank's debt after nationalising it.

Although the transfer will improve Fortis Bank Netherlands' solvency, Bos said the transaction was not a capital injection.

(Reporting by Harro ten Wolde)