* Deadline for final bids on Monday - sources
* Bids to range between 1.5-2 billion euros - sources
* Macquarie, EPH seen as front-runner - sources (Adds details, background on asset disposals)
WARSAW/FRANKFURT, Feb 14 Czech energy firm EPH and Macquarie will submit a joint bid for Net4Gas, the Czech gas transmission system operator owned by Germany's No.2 utility RWE, four people familiar with the matter told Reuters.
German insurer Allianz, too, is still in the race, the sources said, while a spokesman for Czech financial group KKCG confirmed it would submit a "very proper and serious bid", not elaborating further.
The bids, due on Monday, Feb. 18, are expected to range between 1.5-2 billion euros ($2-2.3 billion), the sources said.
"The process is in its final stages," one of the people said.
RWE is selling off up to 7 billion euros in assets by the end of the year to cut its 34 billion debt pile and raise cash to invest in growth areas such as renewable energy. The company has already made disposals worth more than 1.8 billion euros.
Net4Gas operates more than 3,600 km of pipelines, employs more than 500 staff and accounted for about 11 percent of RWE's net profit in 2011.
Infrastructure investors have been looking for assets that yield guaranteed returns, including power and gas grids, because of low interest rates and volatile stock markets.
The sources said that Australian investment bank Macquarie and EPH, whose biggest shareholder is billionaire Czech businessman Petr Kellner, had a good chance of winning the auction.
EPH, made up of more than 30 energy companies, is pushing ahead with a multi-billion euro acquisition plan. In January, the group said it would buy a 49 percent stake in Slovak gas utility SPP from Germany's E.ON and France's GDF Suez for a total of 2.6 billion euros.
Macquarie is a major force in European infrastructure M&A, having already bought RWE's 4,100 kilometre gas network Thyssengas as well as a 35 percent stake in RWE's Czech gas grids.
Macquarie, RWE and Allianz declined to comment. EPH had no immediate comment. ($1 = 0.7442 euros) (Reporting by Agnieszka Barteczko, Christoph Steitz, Arno Schuetze, Tom Kaeckenhoff, Jana Mlcochova and Jason Hovet. Editing by Jane Merriman)