Water management group Aliaxis on Monday made an all-cash offer for plumbing and heating systems maker Uponor worth 1.87 billion euros ($2.06 billion), a 3% increase over the Belgian group's initial bid last month.

Uponor has rejected both offers, arguing they were insufficient.

"It's a question of value. It's a question of maximizing shareholder value. Maximizing the wealth of Uponor's owners," said Hans Sohlstrom, an Uponor board member who leads the Finnish group's response to the Aliaxis bid.

The Belgian bids had attracted widespread attention, he added.

"Practically everyone globally in this industry is aware of the situation and of course, anyone who had any type of interest in Uponor understands that this is the time to act," Sohlstrom said.

"So basically the publicity that Aliaxis has brought to this process has also triggered interest among players in this industry globally."

Swiss industrial group Georg Fischer AG is also exploring a potential offer for Uponor, potentially leading to a bidding war for the Finnish company, Bloomberg News reported on Tuesday, citing unnamed sources.

Georg Fischer did not immediately respond to a request for comment when contacted by Reuters on Wednesday.

($1 = 0.9084 euros)

(F.sReporting by Elviira Luoma, Louise Rasmussen, editing by Terje Solsvik)