Israel has assembled a large system of pumps that may be used to flood tunnels used by militant group Hamas under the Gaza strip in a bid to drive out fighters, the Wall Street Journal reported on Monday, citing US officials.

Around the middle of November, Israel's army completed the set-up of at least five pumps about a mile north of the Al-Shati refugee camp that could move thousands of cubic meters of water per hour, flooding the tunnels within weeks, the report said.

It was not clear whether Israel would consider using the pumps before all hostages were released, according to the story. Hamas has previously said it has hidden captives in "safe places and tunnels."

Reuters could not verify the details of Monday's report. When asked about the story, a US official said it made sense for Israel to render the tunnels inoperable and that the country was exploring a range of ways to do that.

Israel's defense ministry did not immediately respond to a request for comment. The Wall Street Journal said an Israel Defense Forces (IDF) official declined to comment on the flooding plan but was quoted as saying: "The IDF is operating to dismantle Hamas’s terror capabilities in various ways, using different military and technological tools."

Israel first informed the United States of the option last month, the Wall Street Journal said, reporting that officials did not know how close Prime Minister Benjamin Netanyahu's government was to carrying out the plan.

Israel has not made a final decision to go ahead or rule it out, the officials were cited as saying.